Introduction to Mounting Prints

 

Overview

If you intend putting some of your prints up on a wall or in a standing frame then you will have to contend with the challenges that come with mounting prints.  What you will find here is a basic introduction to the best method for mounting prints offering reliability, ease of use and minimal risk to your work. Framing is another subject and not dealt with here except as necessary to explain something else.

Small prints (let's say up to 5 x 7) can sometimes be framed without mounting. That is, they slip into a frame with some sort of stiff backing and this holds the print flat enough owing to its small size.

To display a larger print in a frame or in a free-standing holder usually requires that the print be bonded to a more or less rigid, flat base material or substrate (such as heavy carboard or foam-board) that prevents bulges, buckling or other distracting flaws in the presentation. For reasons presented shortly, my preference is for "dry mount" mounting. There are other ways which can work but I have found them all unsatisfactory, especially for large prints.

Three of the more common alternatives to dry mount are:

  • Spray adhesive - For this method you use a pressurized can of glue. If you try this, make sure the spray is formulated for photographic prints as other types my leak through and ruin the print. The biggest problem with spray is that it goes everywhere. Get some on your hands and it deliberately works its way up your arms to your neck, then downward until your entire body is covered. It is determined to reach the surface of your print which it will soon do in the form of indelible sticky fingerprints and hairy patches. Furthermore, the stuff contaminates your tools such as cutting boards, shears and trimmers. When applying a print to a glue-sprayed backing there is a great risk of static electricity suddenly attracting the print so that it sticks in the wrong place. The desperate attempt to pull it off is usually destructive. Foul language doesn't help. Finally, you have to work in a well ventilated space or, preferrably, out of doors or you will gas yourself. An essential accessory is a hard rubber roller for pressing out the inevitable air bubbles that get trapped by the glue. The roller must be kept scrupulousy free of glue - a near impossibility.  I detest spray. You may have better luck but have been warned.
  • Doube-sided adhesive sheets - A more costly approach than spray but avoids some of the problems. You peel a waxed film off one side of the sheet, exposing a sticky surface and apply to the print substrate. Then you peel off the other waxy film and apply the print. The hard rubber roller is needed once again to remove air pockets. There's no smell and much less risk of adhesive going where you don't want it. Static charge suddenly attracting the print remains a risk. Difficult to use with large prints because it is almost impossible to get the print down flat initially and the roller may not work, leaving air pockets in place or permanent wrinkles. I have had prints mounted this way come loose after a couple of years especially around the edges. Works reasonably well for small prints - much nicer to use than spray - but with larger sizes trapped air bubbles are a challenge.
  • Pre-glued mounting board - This is a thick (maybe 3/8 inch) rectangle of wood or other material approximately same size as the print you want to mount. 8 X 10 and 11 X 14 sizes are common. There's a nice black or other color plastic trim around the edge. One surface has a sticky substance protected by a waxy sheet. The idea is you peel off the waxy sheet, apply the print, work it down with a roller and the picture is ready for the wall. The print should be made slightly larger than the board to make placement less critical and you then trim by running around the edge from the back of the board with a utility knife. Sounds easy and it is. Anyone can do it. The big problem is that, like double sided sticky mounting sheets, air bubbles are very likely to appear and probably cannot be worked out with the roller. There is a solution. First apply a piece of poster board to the adhesive, as if it were the print. Poster board is stiff enough you won't get air bubbles or, even if you do, they can be worked out with the roller as the material is reasonably porous. Finally use the dry mount technology to mount the print itself to the poster board surface. Works perfectly. The boards tend to be costly and the poster board step is a nuisance but the result can be very attractive for unframed prints.

I'm a dry mount bigot so let's just move on to that. With this method you prepare a four layer "sandwich". The bottom layer is the print substrate (the heavy material to which you are mounting the print)  followed by a non-sticky (hence dry) sheet of thin tissue infused with a special adhesive that is activated by heat. The print itself is next (face up - doh!) followed by a "release sheet". A release sheet is a silicon coated sheet that resists sticking of the sandwich to the mounting press platen (see later) - a potentially disastrous situation. You then place the sandwich in the pre-heated dry mount press (there is an alternative discussed below), clamp this down and after a short time the sandwich emerges with the print now permanently glued to the substrate. The release sheet simply falls off. There are no bubbles, there's little if any odor and, if you follow good procedure, no unwanted adhesive hanging around. The method is low cost, apart from the press, by far the easiest of all to use, clean and reliable.

For those who don't know ... a dry mount press is an appliance comprising a heavy flat base with a hard foam/felt covered pad on which the substrate/dry mount sheet/print/release sheet sandwich is placed. Hovering above this is a platen or thick metal plate the same size as the base. The platen is electrically heated and incorporates a clamping handle for lowering it tightly against the sandwich. Heat flows through the release sheet, through the print, into the dry mount tissue and melts the adhesive which then sticks to both the substrate and the print. Pressure from the platen keeps everything nice and flat. The process is much like making a waffle. Time and temperature are somewhat critical but easily controlled.

Dry mounting is initially the most costly (unless you opt for making-do with a clothes iron - see later) mounting method because of the press. In the long run it is by far the least expensive method because it is difficult to ruin a print with this method. It's hard to go wrong with dry mount, providing you follow correct procedure.

 

Equipment (Dry Mounting)

  1. Good quality shears for trimming tissue and prints - Blow $10 on a decent pair and use them for nothing else so they stay clean and sharp. The advantage of shears is they can handle any size of print or other materials.
  2. Rotary trimmer - The bigger the better. Same purpose as shears but these are very expensive for a good one, especially those that can handle large pieces of material. The shears can do almost as well but are awkward and slow. A rotary trimmer is a real pleasure to use if something of a luxury for the amateur on a tight budget. What about the more commonly seen lever-style trimmer with a humungous curved knife? These are less expensive, to be sure. The problem with them is that during operation the blade can get pulled away from the steel edge against which it is supposed to bear. This will leave a rough cut and may even tear some materials. Certainly workable but not nearly as good as a rotary for photo work.
  3. Box cutter (utility knife) - For trimming all materials but especially foam board. Base materials - even cardboard - are usually too heavy for a trimmer or shears.
  4. Long straight edge - as long as the longest side of the largest print you intend mounting. A 36 inch carpenter's aluminum rule works well. This is to lay out cut lines on prints and tissue and, especially, to guide the box cutter when trimming heavy materials. A matte cutter can substitute for a straight edge.
  5. A sheet of cutting mat - This is a self-healing plastic pad that you place under anything you are cutting with the box cutter. It will protect your work surface when the box cutter goes through the stuff you are trimming. These mats are expensive but worth every penny. Available at stationery stores. You could make do with a thin sheet of plywood at much lower cost but the blade will loosen wood fiber debris that you have to be alert for and it will eeventually acquire grooves that interfere with trimming.
  6. A large working surface big enough to support the substrate, tissue and print when fully laid out - I use the top of a deep-freeze. An uncarpeted floor works but is uncomfortable and may be tough to keep clear of debris.
  7. Dry mount press - the bigger the better. Ideally the press will be able to cover your largest sandwich. Presses are expensive. You can economize by getting a smaller one and then squeeze your sandwiches in sections from each end and the sides. The press has to be able to swallow half the sandwich from each end/side for this to work. The only drawback:  takes longer to do. Some say this piecemeal method is apt to leave ridges  or other defects where the platen overlaps occur but I have never observed this.  Alternative to a press: the common clothes iron. This is trickier to use but with practice works well (details later). Reserve the iron for only this usage. You do not want to risk contaminants. Try to scrape up the cash for a medium-size press, at least. I have an old "Seal Jumbo" which will do a 16 X 20 sandwich in one gulp. Using the multi-pass approach it can just manage a 32 X 40 inch piece of work.
  8. Tacking iron - This is a small electrically heated Teflon pad with a handle. It's used for tacking down the adhesive sheets and print before shoving the sandwich into the press. More on this later. Alternative: the clothes iron. Tacking irons are inexpensive so just get one for the convenience.
  9. Teflon spatula - It shouldn't happen but sometimes does that when you open the press after heating the sandwich the latter is magically nowhere to be seen. That's because it is stuck to the platen and getting hotter by the second, which could ruin everything. You may be using a release sheet but these are not absolutely infallible. The sandwich will be loosely stuck and can be pulled off with the fingers but you could get a nasty burn. The spatula works perfectly to pop the sandwich off the platen with no risk to yourself and it won't scratch the platen. Use the spatula for this only. It's not worth it to risk contaminating the press with remnants of yesterday's omelette or bacon grease.
  10. Electronic kitchen or BBQ thermometer - This is to calibrate the press or clothes iron. It has to have a range nearly to boiling point (212F) and a probe on a wire so the probe can be placed in the press while the read-out remains outside. You want the press/iron temperature within a few degrees of what the dry mount tissue requires. I have a very good press but the thermometer on the cover reads low by almost 20F (!!) so beware. If the press is too hot an ink jet print will split and bubble. Electronic thermometers are very accurate and you can get a perfectly suitable one at the supermarket for under $10.
  11. Finally, a really great accessory is a matte cutter. Even if you don't cut your own mattes (although that's easy with a matte cutter), this tool can replace all of shears, rotary trimmer and straight edge. Even a good matte cutter is reasonably inexpensive  - at around $150 from "Logan Graphic". You owe yourself this.

 

Materials

  1. The print itself - the object of the exercise.
  2. The substrate - This is what you are mounting the print to. I like poster board of the type sold in stationery stores.  Prints are usually inserted into a frame from the back. The depth of the opening may influence the thickness of substrate you need. I have heard of people using thick acrylic sheets, aluminum and wood as substrate material. There's room for experimentation. Dry mount tissue will work with almost anything. Just make sure whatever you use is not likely to infuse the print with contaminants over time.
  3. Dry mount tissue - You can purchase this as packages of pre-cut sheets but more flexible is to buy a long roll so you can custom cut pieces. You will, for sure, need to do this for large prints. Tissue meant for mounting conventional paper prints has a high melting temperature in the range of 180F. This is close to the "destruct zone" for ink jet prints. Ink jet paper is coated with resins and other plasticky substances that can't withstand a lot of heat. Get a dry mount tissue with a lower melting point. I like the "DRY_LAM Colortac" available from B&H. It melts at 165F which is perfect. A 24.5 inch by 150 roll is under $100 and suffices for a lot of prints. Resist the urge to use multiple sheets of dry mount tissue to cover an area if the print is too large for a single sheet to do the job (generally not an issue if you can cut from a roll). No matter how carefully you fit them together there is always a visible line in the print where they meet underneath. In some lighting and viewing contexts this may not be a problem - you will have to experiment.
  4. Release tissue - You can also get this in sheets or in rolls from B&H. If you want to save money though ... Epson paper is always packaged with a glossy brown sheet which works perfectly as a release sheet (maybe that's what it is but they don't say so). If you get a roll of Epson paper (recommended for custom print sizes) this comes with a full length of the stuff so you always have enough. I have even tried using large sheets of high quality plain paper (Epson) and this works perfectly too for quick release from the press. You have to be very careful though that there is no exposed mounting tissue that might come in contact with the paper during heating as it will stick firmly to the paper. Recommendation: experiment with these alternatives on a couple of small sandwiches before spending money on dedicated release material. I seldom bother with release sheets because I keep the dry mount dimensions slightly smaller than those of the print. With nothing sticking out the sides there's no risk of bonding to the platen of the press.

Note to deprived Canadians: Dry mount tissue and release paper are almost impossible to find in this country. Save yourself some trouble and just order from B&H (New York). They are prompt, well stocked and handle all the border crossing details for you.

 

Preparation

  1. Print paper ... before printing - Especially when cutting from a roll, the paper may have considerable curl. This risks a head strike while printing. This happens when the paper sticks up too high from the printer platen and the nozzles rub against the paper surface. Worse yet, the head may actually run into the edge of the paper and be damaged although this is rare. Head strikes usually appear as smeared gobs of ink near the top or bottom of the print. You can uncurl the paper by reverse curling it inside a large cardboard roll. From "wet darkroom" days I have an old blotter roll which is perfect for the job. A sheet of print paper reverse curled inside this will lie reasonably flat after about a day. You can also try placing curled sheets under something flat with a bit of weight on top but this doesn't work as well. When cutting/trimming from a roll, plan your cut so that the axis of the paper curl is parallel to the direction in which the printer head runs. This makes it much easier for the printer rollers and guides to flatten any residual curl (there is always some residual curl after flattening).
  2. The print ... before mounting - This must be dry and clean. Immediately after printing an Epson print seems perfectly dry but Epson advises there is out-gassing for about 24 hours. I let my prints lie out in the open for a couple of days before mounting. Why take chances? Ensure the print is free of dust and grit on both sides. Small particles on the backside will produce visible pimples on the finished product. A draftsman's brush is perfect for the job.
  3. Mounting tissue - Same precautions regarding cleanliness as with the print. You will be tacking it down with the tacking iron so don't worry about any curl.
  4. Release sheet - If cut from a roll this will have a curl too but the material is thin and you won't have a problem with it. I still think that at the low temps used with ink jet prints and Colortac you can get away with plain paper or poster-board providing it is quality material, the print is thoroughly dry and you trim so there's no exposed mounting tissue.
  5. Press - pre-warm this to the correct temperature. Initially, calibrate the press using the BBQ thermometer as follows ... Cut a couple of pieces of heavy carboard approximately same thinkness as the probe diameter and place the probe between these (one on each side of the probe) on the press base. This avoids having the platen force the probe too far into the base where it might leave a permanent impression. Now close the platen lid, turn on the juice and wait for the temperature to stablize, at least 20 minutes. It will take some adjustment of the thermostat knob but you will find a setting for the temperature control that results in something within a few degrees of the dry mount tissue melting temperature. Mark this setting on the temperature control and in future you can dispense with the BBQ thermometer. Do not trust the thermometer built into the press until you have calibrated it. Mine reads far too low. If you are using a clothes iron use similar method to calibrate it. Extreme accuracy is unnecessary. Plus/minus 5 degrees F is perfectly OK and readily obtained.
  6. Press - keep it clean. Once in awhile work a vacuum cleaner nozzle in there and clean the felt base. The surface of the platen may acquire debris stuck on there with stray adhesive or whatever. You can feel this with your bare hand when the press is cool. For cleaning the platen I use one of those rough Teflon kitchen pads and a bit of isopropyl alcohol. The pad can provide serious scraping but won't leave scratches.

Most of the following assumes you will be showing the print in a frame that covers and clamps down the edges of the print or that there will be a matte that accomplishes the same thing. A matte is typically a heavy cardboard sheet same size as the substrate that has a cut-out through which the print is viewed. The cut-out is smaller than the interior of the frame opening (as seen from the front or viewing side), providing an attractive border. Prints are sometimes mounted using a frameless/matte-less scheme where the substrate is a thick material and the entire print surface is visible without any framing effect or matte (example: pre-glued boards mentioned at the beginning to this article). Variations in mounting technique for this method are included in the notes below.

If your print frame is matted, adjust your technique accordingly. For example, trim the print and dry mount tissue to something just larger than the matte opening and position the materials appropriately. To avoid exposed mounting tissue, trim the latter slightly smaller than the print. The matte will later flatten the edges of the print.

 

The Process - Step by Step

  1. Prepare the substrate - Trim this so it completely fits inside the opening at the back of the frame. Brush the surface to remove all debris resulting from the trimming process.
  2. Trim the print to  slightly larger than the matte opening - about 1/4 inch all-round is plenty.
  3. Trim the dry mount tissue  Important: Unless mounting the print stand-alone (without a matte or on a thick substrate that will not be framed) you want the sheet of dry mount to have dimensions slightly less than that of the print - let's say about 1/8 to 1/4 inch less in both length and width. The reason for this is to avoid adhesive getting onto your release sheet if you are using ordinary paper for that purpose. You don't need the print glued to the substrate right to the edge because the matte will hold down the edges.
  4. Center the dry mount tissue on the back of the print. On one end only (the shortest dimension) from the back of the print (image side), lightly tack the dry mount sheet in one spot to the substrate with the tacking iron (or clothes iron). Keep some release sheet (you will need the real stuff for this - not paper) between the iron and the print to avoid getting adhesive on the iron although this can be wiped off later while the tacking iron is still hot. Tacking should be at one spot near the edge. It takes just a few seconds of heat for the adhesive to bind sufficiently the tissue to the substrate. The dry mount tissue will now remain properly aligned on the back of the print.
  5. Why all this tacking (see see step 6 as well)? Why not just carry the sandwich to the press and have done with it? The reason is that the dry mount, print and release sheets have a lot of area with a good deal of air between the facing surfaces. Their mutual contact is practically frictionless. The slightest breeze - even that produced by the application of the press platen - is apt to move one or more of these sheets. The result is often a misaligned print, the adhesive going where it's not wanted or the print firmly stuck to the platen where the release sheet slid away.
  6. Center the print on the substrate or otherwise position it on the substrate so it will be properly aligned with the matte opening. If you observed step 3 above there will be no dry mount tissue peeking out along the edges of the print. This will ensure that during the clamping step no adhesive will stick to anything else, including the release sheet. In a perfect world the release sheet is not supposed to pick up anything. It might, however (and if using plain paper as a substitute, it certainly will). If you then re-use it the goo could transfer to your next print. The tiniest outer edge of the print won't be glued down but this doesn't matter as the front part of the frame or the matte will clamp this in place anyway. Of course, if you intend hanging the print without a frame or matte, au naturel as it were, you must ensure the print is held down right to the edge so ignore anything in the foregoing steps recommending you not have the print stuck down to the very edge. You will in that case, however, have to be much more careful in preparing the dry mount tissue dimensions and/or will have to use a proper release sheet (not plain paper).
  7. Along the same edge of the dry mount tissue already tacked to the print, tack the print plus dry mount to the substrate. Place some release sheet (it can now be plain paper) between the tacking iron and the print to avoid the iron possible scratching the print. Again, a few seconds should suffice to secure the print plus dry mount to the substrate. Any slippage or misalignment is now impossible.
  8. Place the release sheet on top of the sandwich. I usually use a large piece of posterboard. This must cover the entire print and it can be plain paper apart from possible mounting exceptions described earlier. You want all of the sandwich under the platen and the release sheet completely covering the print area. For sandwiches larger than the press, work in sections.
  9. Place the whole mess in the press and slowly clamp the platen down. The sandwich will now slide flat while remaining perfectly aligned because of the tacking you did earlier. Wait 30 to 40 seconds (this is called "dwell time") if using "Drylam" product and raise the platen. The sandwich should be lying there all glued together and the release sheet should be loose on top of it. If the release sheet is stuck a bit it always peels off easily with no harm done.  If the sandwich is stuck to the platen that's what the Teflon spatula is for. It works but act quickly or the sandwich may overheat. If the sandwich is too big for the press you will have to clamp and heat it in sections. Do the end where you did the tacking first. This is important as it forces the sheets to flatten away from the constrained end which prevents formation of a wrinkle. After that do the sides and finally the end opposite the initially tacked end. It may work best to do multiple passes with shorter time intervals so as to discourage the formation of ridges caused by expansion of the print, then a final full time interval application to set the adhesive securely. Variations are possible. It should work to do initial tacking in the centre of the sandwich, providing the platen descends squarely and not at a slight angle.
  10. Dwell Time. This is how long to keep the press clamped down. "Drylam" recomends 2 or more minutes but I find 30 seconds or a bit more plenty. Much depends on your materials. If you have an absorbent substrate such as posterboard, it will wick away the heated adhesive over too long a dwell time, leaving dry spots under the print. These will then show up as raised areas and the print is ruined. Experiment first with some small pieces of test materials.
  11. If using a clothes iron you will approach the sandwich as it lies on a firm, flat surface. Cover it with release tissue (or paper) and then work the the surface moving from central areas toward the edge. Try not to overheat some areas by passing over them too often. It's tricky but having used this method in the distant past can assure you excellent results are readily obtained. Because the iron is moving, avoid heavy pressure as this can force up a bulge or ridge in the print just ahead of the iron. That risks producing a crease when the iron overrides the bulge. With all methods, areas that end up not fully glued can usually be flattened later with re-application of heat.
  12.  With all methods, be alert for unglued areas which will present a slight bulge or ridge. Re-application of heat and pressure usually fixes the problem except as noted in "Dwell Time" above. When doing this, proceed extra slowly so as to allow adhesive beyond the bulge some time to loosen and provide a bit of slack where the material in the bulge can go under full pressure. Always works although seldom needed.                                                                                                                           
  13. Let the sandwich cool and you are done except for putting it in the frame. There is liable to be considerable curl from the heat. Just let the sandwich sit there and it will flatten out on it's own within an hour or so. There is seldom anything to be gained by placing it under weights.

Frames come in a vast variety of styles and methods for securing the print inside. If the frame has glass, consider spacing the print slightly back from the glass surface to avoid direct contact. Using a matte accomplishes this automatically. The space reduces the chances of the print sticking or condensation creating a visible defect. Some frames are made with inserts to ensure this separation. Box frames have a wide separation between print and glass and are worth a look.

Increasingly we see prints displayed without protective glass, mounted to a thick substrate which hangs directly on the wall without a frame. This raises concern over accumulation of dirt and what can be used for protection. There are clear plastic sprays developed for the purpose and the ones I have tried work well. Built-in UV protection is usually included. Although I hesitate to recommend it as it isn't specifically designed for the purpose, I have had excellent long-term results using clear "Krylon". Ink jet surfaces are quite robust and endure more cleaning/abuse than most people would think. Ones I have tried without any protection whatsoever have lasted for years with no visible change in appearance. A lot depends on your circumstances - cleanliness of the air, etc.

 

Conclusion

  • Dry mount is a reliable, high quality, easily used way to mount prints of all sizes. It is actually easier or, at least, less risky for the beginner to use than any other method. The materials are inexpensive but presses are costly although a one time expense. You can manage with a clothes iron but this takes more time and requires experience to obtain good results.
  • Alternatives to dry mount are superficially attractive because they avoid the press but are difficult to deploy with large prints. Spray glues contaminate the work area while the stench from the volatile gases makes for a thoroughly unpleasant experience. Air bubbles and other problems abound.
  • Pre-glued boards work extremely well provided you first apply poster board and then the print using dry mount technology. Prints applied directly to the adhesive are prone to trapping air bubbles.
  • Double sided adhesive sheets work well with small prints but may not provide a permanent mount. They avoid the smell and contamination of sprays. Air bubbles are a problem.
  • If your needs involve a variety of frame sizes, purchase materials in rolls. Print paper may have to be pre-flattened before printing.
  • Dry mount presses must be calibrated for temperature. Ink jet papers are in danger at temperatures normally used for conventional papers. Choose a tissue such as "Drylam" that activates around 165F. You can get away with higher temperatures but timing becomes more critical.

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