Paper and Coating
Homemade Baryta-Coated Paper
'I ♥' emulsion coated on baryta-coated Rives Lightweight watercolor paper. The surface characteristic is between the glossy of commercial unsensitized baryta (as sold by Photographers' Formulary) and emulsion on plain watercolor paper.
Revised version published December, 2008.
Caveat: The finished paper is beautiful, but this is a lot of fussy work.
The recipe is carried out in three parts. 1) Blooming the gelatin several hours, 2) Making the baryta paste and adding it to melted gelatin, followed by refrigeration, 3) Remelting the baryta-gelatin, additions, and coating. See Oster emulsion for illustrations of the mixing set-up.
Chemistry needed: Gelatin, distilled water, barium sulfate (you'll need a business license to order this here), Everclear, glycerin, and glyoxal.
Tools and Materials: Thick (1/4") plate glass larger than your paper (10 to 12 sheets), 12 "emulsion well, and 12" (i.e. 11"x14" size) puddle pusher prepared for coating (here). (You can work with a 9" well and puddle pusher, but you will need to work out the different paper and glass sheet dimensions), Rives Lightweight watercolor paper (here).
|Gelatin, hard (250 bloom).||5.6 g|
|Distilled water, refrigerator temperature.||55 ml|
Bloom gelatin several hours in a 250 ml beaker or similar. In the meantime, prepare the baryta paste.
|Barium sulfate||67.2 g|
|Distilled water, very warm||52.8 g|
Note: At no point in this procedure is a safelight required.
Put the barium sulfate in a 21oz working glass set up for Oster mixing (here). Set a small funnel in the small hole in the lid. Start the mixer at lowest speed and slowly add the water through the funnel. After the water is added, lift the lid enough to scrape the inside of the glass. Reset the lid and give the baryta paste another whiz. Remove the lid and whisk and scrape as much of the paste as possible to the bottom of the glass. Reset the lid and mixer.
Melt the gelatin in a waterbath to 45-50°C.
Strain the melted gelatin through a fine sieve stainless steel tea strainer into a clean beaker and immediately add the melted gelatin slowly to the baryta paste in the same manner you added the water to the dry barium sulfate. Again, scrape down the sides and give another whiz. Remove the whisk and stir in 5 ml Everclear with a clean plastic spoon. The mixture will be very frothy. Strain it through a clean stainless steel tea strainer into an 8oz canning jar or similar. You may have to help the last of the mixture through with the back of a plastic spoon. Don't worry about getting all the froth. Cover and refrigerate.
As soon as two hours later, or up to a week later:
Prepare the Rives paper for coating. (I usually do this while the baryta-gelatin is setting up in the refrigerator.) Cut the paper 14 x 20 inches (or work out your own best dimensions). Have a number of sheets of thick (1/4") plate glass (16 x 22 inches) ready with enough flat, level area to set them aside as you coat each sheet. The area where you will be drying the coated paper should be clean and the air should be as dust-free as practical. Since I have a limited workspace, I have built a cabinet for the glass sheets, along the same design as the cabinet for my granite (here).
One at a time, dip the paper in warm distilled water held in a tray larger than the paper. Leave the paper in the water only long enough to evenly wet the paper through. Lift the paper, allow it to drain a minute and then carefully lay it flat on a sheet of glass. Gently scrape off the water and press the paper evenly against the glass with an impeccably clean squeegee (the all-plastic kind sold for wiping down showers is ideal). The moisture will hold the paper to the glass without tape. Cover the paper with a piece of clean plastic wrap or a mylar sheet [Tip: The bags sold for print protection ('Clear Bags') or the bags that inkjet paper come in - cut in two pieces each] so that the paper doesn't start to dry before you can coat it with your baryta mixture. Repeat with five more sheets. Since I don't like to waste paper, I have another five sheets of glass and five more pieces of dry paper ready to wet and squeegee, one at a time, as I need them to use up the last of my baryta coating.
Set the covered jar of cold baryta-gelatin in a room temperature waterbath and slowly bring the temp up to 45°C. The froth bubbles will be all but gone by the time the gelatin melts. It is important from this point on to handle the mixture gently so as to avoid introducing new air. When the waterbath hits 45C, uncover the gelatin, insert a thermometer and gently stir once or twice with a clean plastic spoon. Add 5 ml Everclear and stir slowly and gently for a couple of minutes until the Everclear seems thoroughly mixed in. When the gelatin temp hits 42-43°C, gently stir in 15 drops glycerin. After this has been thoroughly worked in, add 5 ml Everclear and stir a couple of minutes. Strain through a gold mesh coffee filter into a clean beaker. Check the temperature of the mix. When it drops to 37-38°C, add 12 drops glyoxal and stir a couple of minutes. The baryta is ready for coating. During coating, keep the baryta in a 36-38°C waterbath. I make my first sheet on the small side to check the consistency of the mix. If the first coating looks like it has bubbles, add a little more Everclear. A full size sheet of paper will use about 20-25 ml of coating.
I have had good luck with 7-8 wraps of Mylar/polyester film tape (3M #850) on the puddle pusher, but I recommend your own trials to determine what's best for you.
About an hour after you have finished coating all the sheets, lift them off the glass and hang them to finish drying. I have a folding clothes drying rack that I set up in my darkroom. Clothespin the sheets by their corners to a rod on the drying rack and then attach two more clothespins at the bottom. If you don't weight the bottom, the paper will dry in a tight curl.
After the paper is thoroughly dry, take the sheets down and one at a time, tape a sheet, by all four corners, to a clean, dry sheet of glass. With a very soft, clean, lint-free cloth, gently but firmly and thoroughly buff the surface of the paper. This produces a lovely, smooth, semi-gloss surface. If you can do this outside and wear a dust mask, it would probably be smart. There aren't a bunch of cautions involved with barytes, but you will be making an aerosol dust, which is never smart to breathe or let settle around.
To coat the baryta paper with emulsion, repeat the wetting and squeegee steps and coat with emulsion made for wet-coating (i.e. less water).
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