View Full Version : "Curling" of PastelMat

Barbara WC
08-29-2014, 05:08 PM
I am almost finished with the multiple full sheets of PastelMat that I bought a couple of years ago.

When I first tried PastelMat, I bought one of the variety color pads. The sheets were very flat when I tore them out of the pad.

When I got the full sheets, they were "curled" on the short edges- curled "up" if that makes any sense. I bought about 8 sheets in different colors- a pack of 5 dark gray sheets (the pack hadn't been opened) and then 3 "open stock" individual sheets. All curled to some degree, the pack of 5 unopened sheets were curled the most.

The curling hasn't been too big of a deal, but I do have to tape down the edges to make the sheets flat while working.

I originally got the sheets from Dakota (I think). I remember they were shipped flat, well attached to a flat piece of cardboard.

Has anyone else had this problem with full sheets of PastelMat? And is there a good way to flatten the sheets? I tried putting a heavy book on a sheet that was cut into smaller pieces, but it didn't work. I know that the paper probably has to be dampened and then flattened, but I haven't had to time to do that- usually I grab a sheet last minute, cut to size, and run out the door to portrait sessions!

Let me know if you've had the curling problem, and what you've done to make the sheets flat again! thanks!

08-29-2014, 05:49 PM
I've had it -- one edge curled up. I cut it to standard sizes, and saw to it that the curl was cut off and used that strip for testing pastels and colours. The reason I didn't try to flatten it was that the fibre is on card, and that is very difficult to straighten it.
I should have returned it, as I bought it from a shop (ordered for me), but it was only 5 sheets or so, and I had planned to cut them up. The next order was flat. If it hadn't been, I'd've for sure returned it. Which is my recommendation to you, Barbara.

08-29-2014, 07:25 PM
I can't say for sure, but I think most papers that i have curl after a few years. I have one sheet of Pastelmat that I have had for a number of years that is just slightly curled on one end. I had some small sheets of Uart that eventually curled, as do boards of velour. If it is stiff, it seems to eventually curl. Perhaps it is the humidity of where one lives - I really never thought about it much.

Usually I store my paper lying flat (the above mentioned sheets were not - they were stored standing upright on the long side) in a stack large enough so that the weight of the top sheets seems to keep the stack pretty flat.

Not sure what others have experienced. I guess it is a good idea to get only enough paper to last a couple months!


08-30-2014, 02:46 AM
I haven't had much trouble with stored paper curling but I've had pastel papers arrive curled like that. Blick made good when I reported it, and some of the sheet was still usable. I forget whether it was Wallis or Colourfix but they sent me a flat one to replace it.

That was years ago and they changed their packing shortly after, the next order I placed with paper and boards they were strapped in tight between corrugated cardboard stiffener sheets instead of just between stiffeners as in the one that got curled. I think they figured it happened in transit. Haven't gotten anything curled since they did that.

08-30-2014, 11:24 AM
if all older papers are going to curl wouldn't that mean artwork on said paper will also curl?

Barbara WC
08-30-2014, 03:56 PM
Charlie- The curl on mine was quite extreme on both sides of the most affected sheets- I'd have to cut off about 4-5" from both ends to get straight paper. I did cut off about 2" from both ends to use as test paper, just as you did, so some of my paintings are only slightly curled on the edge, but with taping and then final matting, it worked okay. But I kept thinking how much nicer it would be to be able to use the whole sheet if it were flat! This may sound crazy, but I never considered calling Dakota to ask about the problem, nor to make a return! I will do this with my next order if the paper shows up curled- thank you for the suggestion- it just really never occured to me to try to return the paper!

Don- Very good point about storing paper flat- I noticed some slight warping of papers when I used to store them upright- all kinds of paper- watercolor paper included. Then I switched to storing them flat in an art portfolio elevated on the floor in my art room. That worked well for awhile. Then I hit the jackpot- my husband wanted to order a wooden flat file system to hold his photography prints and paper- I asked him to order a few extra drawers for my papers. This has been heaven! All the various papers have stayed very nice since we got the drawers! The PastelMat though never did flatten out- it arrived curled, so I guess it's asking too much to have it flatten on it's own! I haven't had the problem you've had with curling occurring over time though, except for some "warping" of papers when stored upright...

Robert- Glad to hear that Blick took care of you with the curled paper. I seem to remember that the order from Dakota did arrive between stiff corrugated cardboard, taped I believe. It just never occurred to me to call them to tell them about the problem- thought it was just the way the paper normally was I guess! Now that I hear people saying they have gotten flat PastelMat, and know it's possible to get flat paper, I will complain if the next batch is curled! My next order is going to Blick- there is nothing wrong with Dakota- always have had good service from them- but I need to order some other supplies. I've had good luck with Blick too- they have always taken care of any supply defects that I've called about...

Thanks everyone!

08-30-2014, 04:36 PM
I mount mine, so no curling now or later. I used to tape the sanded sheets to my drawing board, but too many times the tape would pull the finish off the paper edges when I removed it, and this looked really tacky. So mounting prevents all those problems. I think it helps keep them in better shape when I put them up in glassine envelopes too, very stable and no bending which loosens the pastel.

Barbara WC
08-30-2014, 05:07 PM
Just a note. I happened to take out my Terry Ludwig handmade color chart this morning. I bought it from Terry Ludwig's website maybe 3 or 4 years ago. My gosh- it has curled horribly! It was pretty flat when I received it- haven't looked at in awhile- the chart is on UArt paper.


Perhaps Don has a point, maybe many papers curl over time!

My "best" paintings have been matted, even the curled PastelMat, and they seem to be in good condition.

Mudfish- can you explain your mounting procedure? Are you gluing/adhering the papers to a backing board before use, or do you mean that you are matting the paintings?

09-01-2014, 10:27 AM
Gluing them to some rigid support. Just make sure the adhesive is archival & the support too. Figured this out after I became a huge fan of PastelBord ($$$ & no large sizes), and had many unsatisfactory results trying to make my own sanded surfaces on various supports.

Moqui Steps
09-02-2014, 01:08 AM
Hello from a greenhorn at WetCanvas.....

I have found over the years that when you have a different surface on one side of a coated sheet as is the case with sanded papers or the cellulose fiber coating on PastelMat, they tend to curl towards the coated side if the sheets are not thick enough to resist it.

This was observed with sanded pastel papers, silver gelatin coated photographic papers and with plain old sandpaper. I think it is caused by how the two surfaces expand / contract differently from changes in temperature and humidity. My watercolor and printmaking papers do not show this tendency because they are the same material on both sides and all the way through.

I really dislike a curled sheet regardless of the medium, so I always dry mount the pastel paper to a rigid board of some kind as mentioned above unless it is just a practice piece. I have had good results with acid free foam core boards, thick mat boards or hardboard / "masonite" sheets. Be sure to seal the hardboard with something archival before you dry mount to it as it can degrade the paper backing if left raw. Around here hardboard is by far the cheapest backer I can find at 44 cents / Sq Ft. plus a bit of sealant, though it does take more work than foam core.

The dry mounting also prevents them from buckling in a frame over time as can happen with a tape / paper hinged hanging type support under the mat, and eliminates the need to tape the paper down while working on it.

A dry mount press is ideal, but they are pretty spendy. Some photo clubs have dry mount presses that the club members can use. Check your local area for something like that. There are artist quality acid free spray glues that work well but you want to work with them in a well ventilated area.

Be sure to mount the paper BEFORE you work on it. You can really do some damage if you try to dry mount after you have worked it.

Barbara WC
09-02-2014, 02:12 AM
Thank you, mudfish, and especially Moqui, for the additional information.

I will have to figure another way around this, mounting before a painting is difficult for many of my paintings, especially the live model portrait sessions. I often have to crop, especially after the model leaves and we are not allowed to photograph. Many of these end up in frames for local shows. And yes, I do use paper tape hinge mounts like my watercolor paintings, which Monqui, you are right, I have many old paintings not stored well that haven't curled...

I guess still possible since I cut my own mats, but I've been moving In the direction of using spacer bars with no mats!

The explanation of the curl makes sense...

I wonder if sealing the back of PastelMat before use would help? Probably not since it would be different material (say gac100 or gesso)...

09-02-2014, 11:35 AM
Just for clarification: the curl Barbara and I talked about re Pastelmat is different from the overall bowing. Our curl looks more like as if moist paper has been stood on its edge and left to dry -- it is clearly a damage in transit, or a manufacturing error.

The other, the bowing, is normally not a big problem when the painting is framed. I once made my own paper, and then I gessoed the backside, while the front got gesso with grit mixed into it. It had bowed, but as soon as I treated the back it straightened.