Picture Frames, Picture Framing and Picture Framers' Blog

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Stretcher Frames Versus Strainer Frames, What’s The Difference?

Stretcher frames and strainer frames are often used by artists, painters and embroiders.  These frames are the wooden framework which hold and support the canvases artists paint or create.  Embroiders sometimes also use these frames for their embroideries since these  can provide the durable tensions needed for sewing and pinning.  That said,  the greatest difference in Strainer Frames versus Stretcher Frames is the cost.  You can buy online a 50x75 cms (20”x30”)  stretched, primed,  ready-to-paint canvas, stapled to a strainer frame for as little as $11.49  The same size, equivalent, stretched, primed, ready-to-paint, canvas stapled to a stretcher frame, priced online,  averages around $146.  You say, wow!   Why the enormous price disparity?  They both look much the same, right?  Well, not quite, there’s more that meets the eye, especially with these type of frames. So what’s different ...  between the two?  Before we begin listing the main the technical differences, we need to point out that stretcher frames are usually custom built here in Australia and hand made by local, skilled craftsmen using local, quality materials. The average picture framing employee would cost his employer around AUD25 x hour. Strainer frames, on the other hand, are normally fully imported, mass manufactured in Asia and mass produced by unskilled labour using the cheapest methods and materials. The average factory employee in Asia can cost his employer a s little as AUD1.35 x hour.  Need we say more?  That said, the first frame, shown below, is a canvas stretched and stapled  across  stretcher frame,  cut from stretcher bars, with machined or routered tongue-and-groove joints at each of the 4  corners. Importantly,  it also includes 2  wooden keys or wedges ( those small, often tapered sections sticking out of the corners )  for each of the 4  corners,  or 8 all up.  stretcher frames always have these either already inserted or wedged,  as in the accompanying photo or inside a small plastic bag.   The keys are  very important since, should the canvas sag with time,  tapping these inwards will expand the frame, making it bigger and thereby straightening the canvas.


Below is a canvas, stretched and stapled across a strainer frame, cut and joined from strainer bars. Note that it does not have tongue-and-groove joints, nor does it have any keys or wedges.  The mitres of the four corners are usually V-nailed and glued permanently and cannot be moved or expanded for additional canvas tautness.  Should the canvas sag or slacken,  it cannot be easily straightened, a whole new frame, or complete re-stretching will be needed.


For those of you who are note familiar with sagging canvases, below is what one looks like, regardless of whether it has been painted, or not. You can see what the problem is, the canvas is not stretched flat.  It is sagging and cockling across the four corners. That is unattractive, looks unprofessional and when a painting looks like this, cannot be properly exhibited thus.

While on the subject of stretcher frames made from stretcher bars, it must be noted that these have a cross section that differ from plain, rectangular section timber. Stretcher bars are near-trapezoid cross section in so far that these are shaped with a back which is square but a top that is slightly slanted.  That means that the perimeter, or the outside of the stretcher frame has a slightly higher edge than the inside.  Thus, when stretch-stapling a canvas onto a stretcher frame made from such stretcher bars, the canvas will naturally become taut and float tight over the frame, resting only on the edges of the four outside sections of the  frame.  This will prevent unwanted paint lines or ridges should the canvas touch or press against the bars when being painted.   Newly-painted canvases not infrequently require tightening as the wood and canvas lose residual moisture, and shrink, even if ever so slightly. This shrinking affects the tautness of the canvas, and make it loose, droop and sag. Should you decide to buy a “proper” stretcher frame with adjustable keys for you canvas, here are some tips about the adjusting the tightness. You should have at least 8 keys, or wedges, two for each joint at every corner. The keys are inserted by their pointy or narrow ends first, into the slots of the joint. Some artists use small cardboard off cuts to protect the back of the canvas when undertaking these manual adjustments. You can then gently, carefully and gradually tap each key into the slot, checking the tautness of the canvas each time you are doing so. With each tap, you should soon notice a gradual improvement in the flatness and tightness of the canvas. This because with each small, incremental tap you will expand the frame and increase  the tension of your canvas. This operation is called “keying” a stretcher frame. Do not over-tap and over-tighten, you should stop as soon as you are satisfied with your keying adjustments.  So now that you have read the advantages and disadvantages of both types of frames, you may ask us,  when should I use a stretcher frame and when a strainer frame? Our practical experience is that most Customers order strainer frames, rather than stretcher frames. This is not only because of the cost ( about one third to that of stretcher frames ) but also because of the nature and quality of the painted canvases to be framed  Most of this art is transient, ephemeral, touristic or commercial. It is deemed transient  they’re just renting somewhere for a while until going overseas. Or ephemeral when the Customers want the art just for a short while, perhaps because they know it’s a fad. Often touristic when overseas travelers bring back home Chinese or Balinese painting for which they paid very little for. At many other times customer know that the painting they have is  mass-produced, commercial art which always devalues and never appreciates.  Only very occasionally do we come across a genuine oil painting  and even more rarely is a Customer prepared to pay for genuine stretcher frames. To find out the cost to stretch-frame an everyday, inexpensive, touristic or commercial, canvas onto a strainer frame you can select Option 8 in our Stretch-Framing Prices Estimator. Please note that the prices estimates are for strainer frames only and not for stretcher frames.  By way of a parting note, we warn that not all canvases can be stretched.  Many inexpensive Asian paintings have been painted with cheap, acrylic ceiling or wall paint rather than professional artists' oils. This means that acrylic canvases are hard, stiff, and that the paint will crack all around the edges if pressure is applied to bend and wrap the canvas around the stretcher bar so as to stretch staple it.  We find it necessary to warn Customers of this, to show them past work samples, and advise them to glue or mount the acrylic canvas onto a board rather than try and stretch it.  Occasionally, when cost is the main concern, we even put them in Ready-Made frames


Thank you so much for explaining the difference between strainer frames and stretcher frames! And even though I’ve had a few paintings framed, I’ve never had this explained this to me, maybe because I never asked. I guess most picture framers just quote for the cheaper strainer frame option because customers always go for the cheapest option, right?
Celeste I. - 27 Jan 2020 05:28 pm

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