Successfully stretching pre-primed linen.
 

As a companion to the thread "Stretching pre-primed canvas",

http://forum.portraitartist.com/show...1&page=1&pp=10

where it was explained how to do this in writing, I am offering this picture tutorial. I just happened to have the camera handy today while stretching a 40" by 30" canvas for a commission.

The support being stretched is a traditional top qualty pre-primed linen that has been glue sized, and primed with a coat of lead white. It's relatively expensive, seemingly inflexible and unforgiving, but very luxurious to paint on. Linen is very different than cotton canvas, and pre-primed linen takes some additional getting used to. Being tricky to stretch without introducing unwanted ripples or stretching tension artifacts, I want to visually share a useful tip and technique of temporarily tacking each corner to eliminate those ripples and achieve professional perfection.

I am currently using Fredrix "Rix" linen on a six yard roll, and "Best" stretcher bars made by Jack Richeson Co. Other supplies are copper plated tacks, canvas stretching pliers (required), an ordinary hammer, and a tack puller. A packing blanket makes a nice work surface.

Oh, let me add as a safety and health precaution, PLEASE wash your hands after handling this lead primed linen. This is very important, as it will leave a slight dusty residue on your hands. Before snacking or lunch break, just clean up!

Let's get stretching,

Garth

Note, I need five more replies to finish this picture tutorial. Thanks!

post 2
 

It is important to secure the corners of the stretcher bars with two screws each to keep the corners from slipping and changing alignment during the application of tacks with a hammer. After this, double check that the corner to corner dimensions still match so the canvas will be square in the end.

Now let's lay out the canvas and cut it to size. For these heavy duty stretcher bars, I allow an extra 2 1/4 inches in cutting the linen, to wrap around the sides and back of the stretchers and leave enough linen for the canvas pliers to get a proper grip.

post 3
 

Now being careful about the positioning of the canvas to the strechers, we may place the first tack in the center of the bar.

Next flip the canvas. Using pliers, establish the proper tension, and place the next tack in the middle of that bar.

Now do the remaining opposite sides with one tack each in the center, using the pliers to establish the desired tension.

Try to get a feel for an even tension each time, using the pliers.

Don't add more tacks out from the center until the corners are temporarily pulled tight in the next step.

post 4
 

Now let's do the special tip of pulling out and tacking each corner to avoid those dreaded ripples. Put a tack on both sides of each corner. These may need to be removed and reset at the time when the rest of the tacks finally reach the corners from the centers.

With the corners pulled out, begin adding tacks out from each center tack, not more than two tacks out on ech side at a time. Keep flipping to the opposite sides and add the tacks even and orderly on every side.

Pay close attention to the tension on the pliers. If the pliers are pulled too hard, the ripple artifacts will be permanently added along the edge for an unprofessional finish. The pictures below explain this.

post 5
 

As tacks are added out every inch and a quarter, or so, the linen begins to feel tight as a drum, and any incidental ripples and dents, magically fade away. Yes, I did make those little pucker impressions with my knees as I cut the canvas. I should have been more careful. As you can see though, with each added rank of tacks, these impressions fade away into eventual oblivion with the increasingly even drum-like tensioning.

Upon arriving to the corners, the last two tacks to each corner need to be off-set, due the the miter-lapping of the corner joints. Looking from the face of the canvas, to the corner at the right, place the tacks closer to the face. Conversely, to the corner on the left, place the off-set tacks closer to the back edge.

Pull out those corner temporary tacks very carefully, as needed, because it is time to fold those hospital corners, and correct the corner tensions. Always fold over onto the same side of the corners, due to the mite-lapping of the joints. Fold to the side to your left, with the tacks to be off-set to the back edge. The pictures should explain this.

post 6
 

Now we are finishing up. The canvas should be flawlessly stretched. One can just about begin painting now! The canvas is evenly primed and just beckoning for some first brushstrokes.

A final step is to remove those temporarary screws, and lightly tack down those remaining canvas overhangs around the back side for the sake of neatness.

Okay we're done. Let's paint!

Hope this has been useful; REMEMBER, wash your hands now!

Garth

Thanks for posting this -- and I can say from experience that Garth's tip about tacking the corners down right from the start does help eliminate those pesky ripples, especially along the long edges.

Garth,
Thank you for posting your pictoral canvas streching instructions. As usual you did a fine job, and I learned alot from it. I do have a couple of questions that I hope you will answer, and I have a problem canvas that I am faced with.

Do you find your heavy strecher bars a pain to frame? I used to use heavy bars but framing was difficult.

I studied Morgan Weistling's video of his streching technique and this is of course quite different than yours.

I have completed a painting that I am very happy with on a 36x40" Clausens type 13 pre-primed fine weave Belgian linen canvas that I strechted on slightly heavier than standard strecher bars. Now that finished painting has these pesky ripples on the sides that I am having problems removing.

When initially streching the canvas it seemed difficult. The canvas felt very stiff, and with this large size, it was dificult getting the result I wanted. After working on streching quite a while I eventually decided to use the canvas as is, and if the painting was successful, and if there was a slight rippling problem, I would re-strech it later.

Well I finished the painting, and it was a good one, and ripples were noticable so I removed the canvas, checked the stretcher bars for correctness, than began re-stretching. After several hours and attempts I am still not satisfied. I took my remaining canvas to a local supplier and they told me that they thought the canvas may have imperfect rippling in it, so to be safe, I sent the canvas back and it was relaced.

In any case, Im still stuck with a painting that I cant get the ripples out and Im not sure what caused the problem to begin with. I have other large canvases that dont have this problem so Im at a loss!

In addition, I learned that pulling the canvas tighter may have even seemed to increase the ripples. The ripples are along the sides and appear only when hit by certain lighting.

I would appreciate any of your your feedback Garth as well as from other who read this post.

Thanks so much,
Mark Lovett

Hi Mark,

I use the same type of canvas you do and restretching after the painting was done has always worked for me, if there were ripples from the initial stretching. Garth's technique (of pulling and tacking the corners very tightly as soon as you've put one staple or tack in the middle of each side) has made a big difference. One of the most well known artists in Seattle has suggested canvas-tightening spray that she buys from online art suppliers that may help. I don't know the particular brand she uses.

Regarding a drying spray, I usually will use plain tap water after stretching a canvas (linen) and then allow the water to dry. When it dries it reoves any wrinkles.

I have done this on a client's painting after delivery due to them. They rested the painting againsy a chair where part of the chair pushed against the face of the painting, waiting for hanging. Unfortunately they didn't notice and by the time they were ready to hang they discovered a indentation. I took it a "magically" removed the depression.

I don't think this is advisable. The water can have an impact on the linen, but more importantly can harm the adhesion of the gesso/lead white/etc that is on the other side of it.

Garth, many thanks for posting this with such care for the photos. A picture is truly worth 1,000 words!

A couple of things, no doubt it depends on what the makers recommend, but in the past, the "dust" that's apparent on the surface of rolled pre-primed linen was likely to be talc, applied as a precaution against fresh primed surfaces sticking in a new roll. It's a good idea to wipe down the surface with a clean rag dampened with denatured alcohol after stretching. You still want to wash your hands, though!

A word about those pricey copper-plated tacks: They look nice, and give you the feeling you've gone the extra mile, but the truth is they are actually less resistant to rust than common blued upholstery tacks. The reason is, there are two processes for electroplating with copper. One, which deposits a thick enough coating to prevent corrosion requires an acid electrolyte which immediately attacks steel. The other process uses a cyanide electrolyte solution which does not attack ferrous metals, but deposits a mere "wash coat" of copper only a molecule thick, just enough to enable steel parts to withstand the acid electrolyte until a significant layer of copper is built up. Guess which single method is used on these tacks?

A few years ago, I ordered a run of solid brass tacks at a stateside mill . . . they cost less than the "art store" copper-plated variety, and were sharper, and harder.

Michele,

Thanks for the heads up regarding the water. I use the water sparingly in a spray bottle, not to the point of run-off. Plus I only do it on those pesky wrinkles that I hope I won't have to deal with (with the exception of my related story) using your's and Garth's method of tacking the corners.

Thanks again.

Garth,

I'm resurrecting your post to thank you for it. I've had such trouble in the past with wrinkles in the canvas. I've used your method, and it works very well.

In my case, I think part of my problem was that I was pulling too tight from the get-go. This time I stretched the canvas with a light pull, then after it was in place and wrinkle-free, went back, took the staples out in small sections at a time and re-stretched as I went, working from side to side as originally. I was able to pull the canvas even tighter this way, with not a wrinkle to be seen. It seemed to me that the (linen double-primed) canvas relaxed a bit after sitting for a while in-between stretching sessions.

This happens to me, too. Now, before I deliver a painting I restretch the canvas and make it just a bit tighter. I've had canvases get all saggy within a few months of delivery and I don't want that to happen again.