Why Frames Tilt Forward

Asked and Answered: 3.0

There is a ten-foot long alcove in our lower-level hallway — we call it the gallery.  This is the one place in our house I can hang whatever I want (i.e., my own art) and switch it out whenever I want.  To facilitate this, I installed a hanging system — basically a slotted rail mounted near the ceiling, with sliding wires and height-adjustable hooks.  These systems cost more than you think they should, but AS Hanging has some more affordable ones.  (You’re welcome for the plug, AS Hanging.)

Frame Tilt - Gallery Rail SystemI was a bit surprised when I hung my first piece and saw how far forward it tilted (see photo at right).  It was not intuitive to me why hanging a fairly light 12″ x 16″ frame on a long wire should cause this.  So naturally, I googled it.

Unlike Fifty Shades of Grey, the topic of tilting picture frames is not discussed a lot on the web.  Where it is mentioned, some surprisingly bad and/or misleading advice is often provided.  For example, take this article from the San Fransisco Chronicle, “How to Keep Heavy Paintings Flush Against the Wall.”  Written by a crafter, the article asserts:  “A heavy painting tends to lean forward under its own weight, which isn’t attractive and can cause wall damage if it pulls its hanger from the wall.”

The second part of that sentence is true enough, but the notion that only heavy items lean forward is false, as my own experience shows.  Furthermore, the solution offered by the author may be well-intentioned but is half-baked at best.  She instructs the reader to cut a piece of wire slightly wider than the frame, attach it to eye hooks on the sides of the frame, and then, “ensure the wire is taut to minimize the chances of the picture leaning forward.”  Sounds reasonable, until you consider the stress this puts on the frame.

The tension in a picture frame wire increases as its angle decreasesThe diagram at left shows how tension in the wire increases dramatically as you make the wire taut.  An 8-lb frame creates exactly 8 lbs of tension in a vertical wire, but if you string the wire tightly across, that same 8-lb frame will produce over 90 lbs of tension in the wire, pulling the sides of the frame inward and possibly crushing the art.

Stretching a wire tightly across a frame is about the worst thing you can do, especially with a heavy piece of art, says The Fine Art Trade Guild.  This has not prevented people — even decorators and sellers of gallery systems — from recommending the practice.  It is much better for the integrity of the frame (and the art) if you leave some slack in the wire and hang the item from two widely-spaced hooks at 45-degree angles, as shown later.

All well and good, but it does not really answer my question: why do frames tilt forward?  Having failed to find a good explanation on the internet, I decided to answer this myself.  Bear with me, fascinated readers.

Why Framed Pictures Tilt - A Side ViewThis side-view (click to open a larger version) may help you understand what is going on.  Figure A shows a frame hung on a wire attached to its top-center.  Now this is a really bad idea, because the entire weight of the frame would pull on the threads of the hook.  But I show this just to illustrate that there would be no cause for this frame to tilt.  The real reason that a frame tilts forward (see Figure B) is because the wire is attached to the back of the frame, while the center-of-mass of the frame is in front of the attachment point.  This creates a torque that causes the frame to rotate.

The frame will rotate until its center-of-mass reaches the lowest possible point.  In the case of the free-hanging frame, it is where the center-of-mass is directly below the attachment point.  Figure B shows how the center-of-mass of the tilted frame (black arrow) is slightly lower than when the frame is held straight up-and-down (red arrow).

Most people in the Northern Hemisphere hang their pictures against a wall — I know I do.  The wall changes the equilibrium position of the frame (Figure C) such that the frame does not tilt as much as it would otherwise.  This is because the wall pushes against the base of the frame, counteracting some of the torque.

Where one attaches the wire makes a difference in the amount of tilt (compare Figure C to Figure D).  Websites offer various guidance on this.  Most advise you to attach the wire to the frame one-third of the way down.  A few say, one-quarter of the way down, or a certain number of inches from the top.  Is there a definitive answer or only opinions?  Or, as Mitch Hedberg asked, who is the real hero?

The hero in this post is geometry, along with a small dose of physics and calculus.  We are going to solve this problem for the benefit of man-and-womankind.  Don’t worry, there are no equations involved… until the appendix.

Diagram of Forward Tilting FrameHere is the setup (click image to enlarge).  A frame of length f is attached to a wall by a wire.  The slack in the wire (the maximum distance one can pull the wire away from the back of the frame) is w.  The wire is attached to the frame b inches from the bottom of the frame and pivots freely at the wall and the frame.  The center-of-mass of the frame is halfway down the frame and distance d from the back of the frame, where I assume the glass is mounted.  We know  f, w, b and d, and we want to find g, the gap between the top of the frame and the wall, at its equilibrium position — the lowest possible location of the center-of-mass.  This would be the maximum value of y1 + y2 + y3 given f, w, b and d.

Chart showing forward tilt of a picture frame varies with frame height and depth of the glassIt took me a few hours (and a second try) to find the right approach and eliminate errors in my calculations, but I got there. The chart at right (click to zoom) shows how slack in the wire and the position of the glass affects forward tilt, for frames of various heights.  Here, I assumed that the wire was attached one-third of the way down from the top of the frame, as most so-called experts advise.

The solid lines in this chart correspond to 10-inch, 20-inch and 40-inch-high frames with a center-of-mass 1/2-inch from the back of the frame.  You may be surprised to see that short frames tilt forward more than tall ones, when one follows the “one-third rule” and provides the same slack in the wire in each case.

The dashed lines show how moving the center-of-mass 1/8-inch to the front or back affects forward tilt, for a 20-inch high frame.  This may seem insignificant, but a 1/8-inch change in the depth of the rabbet could increase the gap at the top of the frame by 25 percent.  It is simple physics — the farther the center-of-mass is from the back of the frame, the greater the torque and the more the frame tilts.

The next chart Chart showing how the wire attachment point affects the forward tilt of a picture frame(click to zoom) shows how fastening the wire at various distances from  the top of the frame affects forward tilt.  For a given amount of slack, attaching the wire closer to the top reduces tilt.  Knowing this, one may ask, why shouldn’t we just forget the “one-third rule” and attach the wire one-sixth of the way down from the top?

Here is one reason: the closer to the top that the wire is attached, the less slack you can allow without the wire being visible.  So the “one-third rule” represents a compromise solution for traditional one-hook installations — some forward tilt is accepted for the sake of having more slack and lower tension in the wire.

Interestingly, the weight of the frame did not enter into my calculations.  This means that a sheet of foamboard having the same dimensions and the same center-of-mass as a wood frame would tilt the same amount when hung the same way.  I have not physically tested this, but you are welcome to disprove it.

So it is not true that “heavy” frames tilt just because they are heavy.  Frames tilt forward more when the wire is attached closer to the center, when the slack in the wire increases, and when the frame is front-heavy.  In typical hanging situations the forward tilt is usually less than 1/4-inch.  But when the frame is suspended on a long wire, as gallery systems do, the tilt can be noticeable — 1 inch or more for a 20-inch-tall frame.

The Bottom Line

frame-calc-diagSo what have we learned and what do I recommend?  If you want to use hooks and wires and you want to hang pictures close to the wall without undue stress on the wire or frame, I suggest using two hooks and  45° wire angles, as illustrated in the diagram at right. This may look a little complicated but it is do-able.

In the original version of this post, I provided a formula to help you with the installation, but in practice, it didn’t go far enough.  So I programmed a two-hook frame hanging calculator and posted it in a companion article titled (what else) The “Hang It with Two Hooks” Calculator.  This online calculator suggests where to fasten the D-rings, how to install the wall hooks, and the length of wire to cut.  This makes the task much easier.

Yes, two hooks present the added challenge of ensuring they are level, but this post is all about reducing forward tilt without stressing the wire or frame.  If you are up to the task of carefully positioning two hooks, you might consider eliminating the wire altogether and hang the frame directly onto the D-rings.  One drawback to this method is the visibility of the hardware; the other is the extra precision that is needed in mounting the hardware.

But what about my gallery hanging system with the long cables?  Here, since we have to rely on a single hook, I suggest wiring the frame according to the one-third rule, with just  enough slack so that the cable hook will engage the wire close to the top rail of the frame.  Then, screw an offset clip to the top rail,Offset Clip slightly off-center, and tuck the cable behind the clip.  For a 20-inch-tall frame hanging 30 inches below a cable track, this will reduce the forward tilt from nearly 1-1/4 inches to less than 1/2-inch.

Others have used Velcro strips for this purpose instead of offset clips, which is a nifty idea if you don’t mind attaching something to the dust cover with adhesive.

So now you know and so do I.  Asked and answered.

____________________________________________________________

Appendix: Calculating the Forward Tilt in a Frame Hanging on a Wall

I provide a full derivation of the problem here.  If you would rather not go there, please refer to the diagram above.  We want to find the gap g between the frame and the wall, given the known variables w, d, f and b.  To get there, we first need to find an expression for y = (y1 + y2 + y3), then use calculus to find the max value for y and back-calculate g.

I found it easier to solve for y in terms of the angle θ formed by the bottom of the frame and the wall, and then replace sin θ and cos θ with our known variables.  This ultimately led to the following expression for y:

Expression relating the center-of-mass of a hanging picture frame to its forward tilt

To find the maximum value of y, and the gap between the top of the frame and the wall at that location, we need to differentiate this equation with respect to g, then set dy/dg = 0 and solve for g by iteration:

Relationship among the parameters of a hanging picture frame at equilibrium

This is how I generated the data for the graphs in the body of this report.

[This post was updated October 4, 2015, with simplified expressions, updated charts, and a link to the complete solution.  It seems to be a popular post.]

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22 Responses to Why Frames Tilt Forward

  1. Erica Hyatt says:

    Craig- you are my hero! As a professional painter, ex-framer and recovering perfectionist you have provided exactly information I needed! Thanks to your diligence and gracious sharing of your calculations I can breathe easier when hanging my upcoming exhibition! Thank you from the bottom of my heart!

    Erica

  2. Denise Simpson says:

    Smart – the exhaustive math in this answer is way above my pay grade. I am very grateful for your commitment to finding the solution. I have in the past thought the answer was to shorten the wire so with my most recent atempt to hang a picture without the forward lean, the center of mass would have had grave consequences due to the weight of this peticular frame and the sentimental value I place on It. I just finished repurposing an old frame and im so please with the results I knew I had to search out a better solution for proper hanging. Thank you again. Denise

  3. ANDREW says:

    I have a much easier solution. Buy Quakehold rubber adhesive. Pull some small bits off and roll them into balls. Squeeze them on the top inside of the frame and press to the wall. The frame will hang perfectly straight. Total work time: 10 seconds.

    • Craig says:

      Dear Readers:

      Recommended uses for QuakeHold Museum Putty include: keeping objects on shelves from shifting position, mounting posters (without frames) to a wall, or preventing the bottom of a frame from tilting — which is a problem only if the frame was not hung on center to start with. Nowhere does it state that the putty can be used to hang framed art without wires or hooks. It is possible that the putty is strong enough, when used with a wire and hook, to hold the top of a frame closer to a wall. But the putty is not recommended for painted or porous surfaces. So if you have glass or metal walls, or live in a dorm, this product may be right for you.

  4. Aaron says:

    I love nothing more than the application statics, calculus and geometry to real life problems. You are my hero of the week. Expect your page to show up in a high school calculus class sometime soon.

    • Craig says:

      Aaron, thank you for reading, and for your comment. I keep thinking that this problem may have a simpler solution than my contorted approach to it, but I will leave that to high-school students of the future.

  5. John Drake says:

    I have several old and delicate oil portraits that are in jesso wood frames, large, most are 40″X32″ approximately, some on wood panels, some on canvas, so weight varies. These have had fairly poor care and are in need of conservation work in varying degrees, which is an entirely different subject and set of questions. That said, I’d like to hang some of them and would like some good advice. I found that the screw eyes and wire were in bad shape, small and loose and although they were replaced some 30+ yrs ago, are of generic hardware store variety, zinc plated, not big enough(?), or well mounted. Some have much older fastenings and very fine stranded, heavy gauge copper wire , some finely twisted steel or iron wire, I guess, black and stiff, kinda “crispy”. The “original” holes in the back of the frame probably correspond to the “1/3 rule” but definitely seem to allow for forward tilt. And they are fairly wallowed out, requiring a larger diameter screw. Actually, these were likely originally hung with a vertical wire set up from picture moulding on high walls, as there are ancient holes in the top of the frame but these may have possibly mounted an early electric light or sconce.
    I’d like to place 1 7/16″ brass screw eyes on the back of frame, following your guidelines at 1/5th of ht, “c”, from the top of frame. Then use coated wire, possibly doubled, (not for weight considerations, these paintings don’t weigh much, 12-18lbs.) just mass for the hook and possibly tension relief, don’t know if mass or wire size effects that at all. And finally, what type of hook to use, whether to put two on wall to get the right spread and angle for wire since these paintings are so big or if just one will work. And is it OK to use a much larger hook regardless of true weight but more specific to size of piece and/or wire? Thanks very much

  6. Craig says:

    Mr. Drake, thanks for reading. Please be aware that I am not a professional framer, rather a hobbyist and former engineer. That said, my biggest concern, based on what you described here, is the condition of the wood. If the wood has seen moisture or high humidity and is very crumbly, then I would worry about the screw threads pulling out of the back of the frame — in that case I would reinforce the back of the frame or take the frames to a professional framer for advice. But if the wood is in good shape, I would recommend:

    (1) Use D-rings instead of screw-eyes. D-rings lay flat against the back of the frame, so there is less forward-tilt. Screw-eyes create more torque at the wire-attachment point, putting more force on the threads and acting to pull the threads out of the wood — throw those screw-eyes away.

    (2) Drill new holes, slightly smaller than the diameter of the screw for the D-ring. Don’t use the old holes. Don’t worry about whether you are exactly 1/5 the way down.

    (3) I like to use #5 coated wire. This site — https://www.usaoncanvas.com/include/guide_picture_framing_wire.php — shows the breaking strength for wires of various gauges. Looks like #5 coated wire would be good for you. It is not necessary to double the wire — that would only be needed if you were forced to use a light-gauge wire for some reason. Doubling the wire reduces the tension in each individual wire, but does not change the overall force where the wire(s) attach to the frame. For attaching the wire onto the D-ring, a good technique is shown here — http://painting.about.com/od/howtoframepaintings/ss/hang-painting.htm#step3

    (4) I tend to use the smallest wall hooks I can get away with (with safety factor of course) so that they are easier to hide and make a smaller impact on the wall. Using two hooks, positioned as shown in the figure, means you can use smaller hooks, because the total weight will be shared by two of them. Two hooks are also better than one, with respect to reducing the stress on the frame, as my post describes. When placing your second hook, it helps (important) to use a level.

    I can understand why you might want to use larger hooks — a larger hook is easier to “find” with the wire, when hanging the picture. You may need to move your D-rings a little further down on the frame, to make sure those large hooks are concealed by the frame. In any case, be careful that the hook is not so large that it touches the back of your artwork/canvas (if the canvas is exposed in the back).

    Good luck!

  7. That’s helpful of you to post a graph about the frame size and how it correlates to certain angles. I have a few big pictures to hang up, I feel like I need an accurate hanging tool to make it work out.

  8. jsinger says:

    You had a problem and, with no general solutions at hand, you found a solution using a combination of mathematics and trial & error. It seems that your solution is just that; “your solution.” A general solution would include weight(s) (via ‘mass’) to determine COG, friction forces, torque, pre-equilibrium moment of inertia. In short, the solution side-steps Newton’s 3rd Law of Motion with ‘rules of thumb’. Also, it seems we are to assume that all frames have a uniform material-density which is negligible to their structural integrity. You mock the “1/3 rule” in lieu of a “1/5 rule” which is merely trading one problem for another. Wouldn’t it be worth the extra hardware to reinforce the entire frame and maintain precise control of the tension and location of the hanger area(s)?

    It’s nice that your problem is solved and that you even shared your results. However, others may benefit more from the “1/3 rule” that applies glass-supporting tension on the frame’s sides and relief for the frame’s bottom. Maybe the “so-called” experts are actually speaking from a position of experience and expertise.

    • Craig says:

      With all due respect, jsinger, mass and coefficient of friction appear nowhere in this analysis, nor should they. This is equilibrium mechanics, not dynamics. The center-of-mass of the frame “wants” to be as low as it can be, and that’s really the only important factor here — the rest is geometry. If the picture has not been hung “at rest”, it will get there sooner or later, with any little vibration in the wall that allows it to find its equilibrium.

      With respect to my assumption of uniform back-to-front weight distribution of art frames… of course there isn’t. It’s a simplification that most people tackling such a problem would make. The glass, if it is present, makes up most of the weight of a frame, and so its contribution to the center of mass should be given the most “weight” so to speak. The variable “d” in my equations represents the back-to-front location of the center-of-mass, wherever it is, but is most likely (for the purposes of most readers) to be where the glass is.

      Jsinger, you suggest there was some kind of trial-and-error involved here. No, there wasn’t. I provided the justifications for my recommendations and you are free to dispense with them. If you think mass is important with respect to forward tilt, you are free to do the experiment that I suggested, which was to hang a sheet of foam-board on the wall and see if it tilts forward the same as a heavy frame does.

      By the way, glass can break if there is too much tension on the wire pulling inward on the frame. The point of this article was to help people resist the temptation to string a taut wire across the frame, in the hope of making their pictures hang flush against the wall. There is enough bad advice about this to go around. I stand by the physics presented. I hope you have a great day.

  9. Nick says:

    Excellent post.

    Question: I’m attempting to hang a heavy, wood-framed mirror from an AS Hanging wall mounted track system. I’m worried about the forward tilt. I plan on using two cables, each going down to its own D-ring mounted on the frame.

    Is there anything about the following application that you think could be improved upon: 1) position the d-rings 1/5 from the top of the frame, 2) add the offset hardware to the top of frame so that the cables (each running from its own D-ring) will form 45 degree angles with the vertical sides of the frame, and 3) install those little bumpers.

    Would that be the best approach for minimizing forward tilt?

  10. Craig says:

    Hi Nick, if I understand correctly, you are going to use (for weight purposes I assume) two cables, each of which will run vertically from the track to individual D-rings on either side of the frame. In this case, yes, I would suggest attaching the D-rings 1/5 of the way down, but you could go even higher. The 1/5 (or 1/3 or whatever) rule and the 45-degree angle is meant to cover applications where there is a wire strung from one side of the frame to the other. You are not going to have a wire running from side-to-side so those comments do not apply to you. So, you could go ahead and attach your D-rings 1/5 the way down — but to minimize forward-tilt, you are still going to have to tuck each of the cables behind an offset clip that you attach to the back of the top member of the frame. If that amount of tilt is still too much, you would have to fasten offset clips (or equivalent) to the wall somewhat above the frame, and run the cables behind those clips also, but that might be unsightly. Just some thoughts. Good luck.

  11. Craig says:

    Nick, one more thought — if your frame has very heavy glass installed, you might also consider attaching two D-rings to the bottom member of the frame, maybe 1/5 of the way in from each side, and run each cable from the track down through the D-ring on the side and finally hooked onto the bottom D-ring. And then consider attaching corner braces to strengthen the joints between the bottom and side memberrs.

    • Nick says:

      Thank you for your helpful comments! Yes it’s very heavy glass. I’m doing a cable system (secured to the ceiling) because I don’t want to drill into the brick wall the mirror will be hanging in front of. I think I’ll just attach the cables high up on the frame (maybe running down to the bottom member), try your offset clip trick, and cross my fingers.

  12. Craig says:

    Nick, with due respect, don’t cross your fingers with respect to the weight of the mirror. Please measure the weight of your mirror and give yourself plenty of safety-factor when it comes to the cables and hooks. And do make sure your attachment points are secure. Good luck.

  13. Mike says:

    I found your post after finding the same issue with a cable hanging system and had the following questions.

    1. One of the suggestions on the AS Hanging site was to put 3/4″ bumpers on the bottom of the frame, propping it out from the wall. I assume this moves the hinge point, but does it affect the gap at the top of the frame?

    2. The track at the top positions the cable center at 1/4″ from the wall. Does this affect the gap?

    3. One reason to use a cable is to hang multiple pieces on each cable. Does the weight of subsequent pieces affect the gap.

    4. Does clipping the cable to the top of the frame or using a hook at the top of the frame, e.g. a saw tooth hanger, simplify the equations?

    It would be very helpful to have a spreadsheet with the equation and be able to type in the variables, frame height, cable length, etc. and read out the gap. For example I might test how far down the wall I could move the track to shorten the cable and reduce the gap. My maths are a bit rusty!

    Many thanks for your efforts.

    • Craig says:

      Hi Mike, thank you for reading and for your questions. My answers are as follows:

      (1) The effect of bumpers placed at the bottom of the frame — well, I would have to re-solve the problem to quantify this, but allow me to share with you the results of the “live” experiment that I just did. I have a 24″ tall painting hanging in my gallery. The combination of cable and slack in the wire is 29-1/2″. The ceiling cable track is about 3/16″ from the wall. The anchor point of the wire is 5″ from the top of the frame (a little more than 1/5 the way down). I do not have an offset clip at the top to hold the cable against the painting. There is no glass. The gap at the top is 1-1/4″. Now, here is the interesting part. I placed a 3/4″ thick shim on the wall at the base of the painting to simulate the effect of the bumpers you mentioned. The gap at the top of the painting increased to 1-1/2″. So bumpers would make the whole painting float out from the wall, and the gap at the top would be larger than before.

      (2) Does the distance of the track from the wall affect the gap? Again, I would have to re-solve the problem for this geometry, but I offer this thought-experiment. Hold the frame by its wire in mid-air, as I illustrated in Figure B in the blog post. This configuration has the greatest-possible forward-tilt — nothing is constraining it. Now, as you move the frame closer to the wall, eventually the bottom of the frame will touch the wall — the wall will “push back” on the bottom of the frame, pivoting the bottom of the frame forward and the top of the frame backward. The minimum possible gap at the top will occur when the wire is attached to the wall. So the answer to your question is, yes, the farther that the ceiling track is from the wall (all other things being equal), the more that your frame will tilt forward.

      (3) Your question about multiple pieces hanging on the same cable is interesting and challenging, because it does bring weight into the equation. This problem cannot be answered by geometry alone, but I offer another thought experiment. Start out by hanging a heavy painting on a long cable. Now, halfway up the cable, attach a piece of foamboard. You will see little if any effect. But let’s say you now switch the positions of the two items — you hook the painting halfway up the cable and hook the foamboard to the bottom. You will see that the tension in the cable below the painting is so little that the bottom of the frame will press the cable against the wall, and the foamboard will hang close to the wall. Now, in part three of our thought-experiment, remove the foamboard and hang another heavy painting at the bottom of the cable (we assume the cable is strong enough). The lower painting will create much more tension in the cable than the foamboard did, and depending on the ratio of the weights of the upper and lower paintings, the cable may now be taut enough to keep the bottom of the upper frame from touching the wall. So you see, this gets complicated. Your best bet, if you wanted to double-up on paintings on one cable, would be to tuck the lower half of the cable under an offset clip attached to the wall, concealed behind the base of the upper painting. But this defeats the purpose of the cable system, yes? To minimize tilt, you would be best-off hanging the heavier painting higher on the cable and the lighter painting below.

      (4) Unless you have a very light piece, like a 8×10 document, I would personally not use a sawtooth hanger at the top of the frame. Yes, it solves the forward-tilt problem, because there is no slack, because there is no wire! For heavier pieces, as I mentioned in the blog post, you can also mostly eliminate tilt by hanging the piece from D-rings mounted on each side of the frame.

      Last but not least, the equation I presented cannot be solved analytically. I had to find each of the data points on the graph by iteration (trying a range of values and zeroing in on the solution, using a spreadsheet of course). I could write a php program to do the iteration, but it’s not the highest thing on my list right now… too many other irons in the fire. But thank you for your interest.

  14. P Bolton says:

    I was watching an old movie and googled why did they used to hang paintings tilting forward. I must say yours was the most thoughtful and thorough answer. Picture hanger/rocket scientist, you are! Thank you

  15. Anonymous says:

    Thank you. The best post on the internet about hanging pics and wall-tilt.

  16. Rich G says:

    Great post. I found it while I was trying to find out why hanging paintings/pictures at a slant was THE way people did it back in the 1800’s. You almost never see anything hanging flush in the old photos of shops and homes.

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