Cold Mounting with Dry Mount press

[shayok]

I've been dry mounting type C photographs with a Seal 350 heat mount press using Colormount tissue. For a variety of reasons I'd love not to use heat, and instead use starch or spray type adhesives. I believe people typically use a vacuum press for this kind of thing. Is it possible to use the heat mount press (with the heat switched off) for this? If at all possible, my guess is one would be restricted to pieces that fit under the press in one pass - is that correct?

Regards.

-Shayok

[wpfay]

Shayok,
Honestly it sound like a step backwards to me. There are all kinds of issues with the spray adhesives that are basically solved in using a heated dry mount press.
To answer your question though, I don't think that a mechanical dry mount press exerts enough pressure to do what you want it to do. The vacuum presses exert a more uniform pressure and they reduce the amount of moisture in the item being mounted and the substrate which helps to avoid the dreaded air bubbles behind the photo.
If you are going to experiment with spray adhesives, I would stick to the solvent based sprays for C prints (3M Photo Mount). The body of the print is primarily plastic (RC paper), and the water based starch won't bond well to it.

What is it that has you shying away from dry mounting C prints?

[Bill Henry-]

… my guess is one would be restricted to pieces that fit under the press in one pass - is that correct?


No. Whether you’re using the press hot or cold, if you have a “buffer sheet” (for lack of a better term) which is a few inches larger than your platen, you can essentially dry mount to over four times the size of your press.

I don’t know the size of your 350, but we have a 500T whose platen is 34 x 26 inches. We use a sheet of double sided, smooth mat board (usually Crescent #33) which is cut to 37 x 29. When we dry mount something oversized, this “buffer sheet” is allowed to spill over the edge of the items to be mounted by 1-1/2 inches on all sides. When the platen is lowered, this “buffer sheet” acts to prevent the seam which ordinarily would appear at the edge of the platen.

Just make sure that the pressure of the press is consistent in all parts of your press and you should be okay.

And, if you use a ColorMount Cover Sheet (the one with the glossy surface) you should be able to mount type C prints without any problem.

[shayok]

The reason I want to move away from heat mounting is that it changes the surface of the glossy Fuji Crystal Archive paper in a certain way - makes it sort of splotchy looking in spite of the use of the glossy ColorMount Cover Sheet. The change is not visible at normal viewing angles, but if you see the reflection of a strong light source in the print, it is clearly visible, and that bothers me somewhat. It becomes even less perceptible under regular glass (but is more noticeable with AR glass).

If none of you see this effect under similar viewing conditions, I would have to conclude that I'm doing something to "damage" the print. My press doesnt heat totally uniformly; with test strips I see it reaches 175F at the edges and 225F in the middle, and this is the setting I have to use because the mnimum bonding temp of seal tissue is 175F. I cook it for 60 sec in each pass for as many passes as is necessary (one or two typically) to cover the print . If too high heat was the reason for the damage, I would think that the edges of the print that were cooked only once shouldnt suffer.

I should also say that I tend to err on the side of a tight bond rather than surface imperfections because my prints have to endure variety of conditions, displayed as they are at outdoor art fairs and transported and stored in a van whose interior temperature can change quite a bit.

[JFeig]

I would say that a 50° variable from the center of a platen to the edges is unacceptable after it has had time to equalize. I suggest that you have a close look at having that press serviced.

[shayok]

I would say that a 50° variable from the center of a platen to the edges is unacceptable after it has had time to equalize.

It does sound outrageous to me too, but if the temp was the reason, the edges of the print (where the temp was low) should be fine, shouldnt they?

[Dave]

Shayok ...another problem with your temperature variance is that Nielsen/Bainbridge states that their foam core board will melt at temperatures over 220 degrees.

Call SEAL at 888-240-6021 Ext.5307 to see what needs to be done to rectify the uneven heat problem. They are great folks to deal with and should be quite helpful.

[Jim Miller]

We used to dry mount nearly all the photos we framed, but today we mount only the ones damaged by creases or wrinkles. Why permanently mount a photo in good condition? It costs more in labor as well as materials, it is invasive, and it isn't usually necessary.

Instead, use edge mounts. For general purposes, we make ours out of scrap clear film and strips of 3M #889 tape. Rip the clear film scraps into 1/2" wide - 3/4" wide strips -- length doesn't matter. Rip the 3/4" wide tape in half, making 3/8" wide strips. Put them together, and in about 15 minutes you can make a month's worth of mounting strips for less than the price of lunch.

We have always hinged or edge-mounted important papers in good condition, including photos. For preservation jobs we use folded strips of Japanese paper, carefully glued to the alphacellulose mount board. No glue on the art paper.

[shayok]

Why permanently mount a photo in good condition? It costs more in labor as well as materials, it is invasive, and it isn't usually necessary.

Instead, use edge mounts.

Does edge mounting hold 16"x24" or 27"x27" size RC prints flat under changing conditions of heat/humidity? That's what SOME customers/images need.

I'd be really eager to know that there are framers out there who are not seeing the kind of change in the surface under the critical examination I describe with heat mounting.

[Val]

Like Jim, I used to drymount most photos automatically.

Now....rarely. Because of the challenges of so many different types of ink, processing, paper, etc, I'm never quite sure what they are (and most of my customers don't either) and what might happen in that press. Hinging, corner mounts, whatever, but rarely drymounting anymore. They're not "justaphotos" anymore.

I like Jim's suggestion of edge mounts, and now that I have a big ol' roll of Melinex, will start trying that.

[Jim Miller]

Does edge mounting hold 16"x24" or 27"x27" size RC prints flat under changing conditions of heat/humidity? That's what SOME customers/images need...

I guess extreme temperature/humidity changes could bring on some wrinkles, if only temporarily. However, a properly-closed frame with fillers and a tight dustcover on the back, and an air space under glazing, would slow the rate of change inside the frame to the point that any sort of paper item should adapt slowly enough to avoid visible wrinkles.

Please note that edge mounts are NOT like corner pockets. Corner pockets force the paper to stand on it bottom corners, which could allow its mid-section to slide, creating wrinkles in the lower quadrants; usually at 45 degree angles. That sort of wrinkling is due to gravitational stress. Environmental conditions might aggravate that damage, but it might happen in perfect conditions, as well.

Edge mounts support the entire bottom edge, and may also be used full-length on the top and sides. Properly installed, edge supports retain all four edges, placed with a slight allowance for normal expansion & contraction.

Only a few artworks larger than 16x20, which we have framed with edge supports, have come back for new mats or glass replacement, but I have yet to see one that is not still flat.

If a photo mounted by edge supports becomes wrinkled by some extreme environmental exposure, you could permanently mount it later. On the contrary, if a dry mounted photograph experiences any kind of damage, it is probably unrecoverable.

There is no such thing as a perfect mount, but at least edge supports are fast, easy, cheap, chemically inert, completely non-invasive, and reversible without special procedures. Can you beat that?:shrug: