Best tool to apply liquid emulsion?

[Colin Corneau]

I've got Liquid Light, not sure whether to use a brush (and if so, any particular type) or some other method to apply it to paper.

Would fine-art paper be ideal for this product? Some papers are advertised for use with platinum/palladium due to their clean white base - would these be a good fit?

I'm simply looking to make a quality, hand-crafted print - I don't care about texture or printing on canvas or what-not.

Many thanks

[Colin Corneau]

For example:
http://www.bostick-sullivan.com/cart/home.php?cat=254

Although I also have a number of traditional Chinese calligraphy brushes for prints 8x10 or smaller.

[JOSarff]

Colin:

You can also use a glass "puddle pusher" rod. Wrap a turn or two of celophane tape around both end of the pusher, and put wadded paper towel in the ends (if it's a tube). The liquid emulsions are a b*tch to clean out otherwise. The tape makes a gap to give an even coating. Denise Ross at 'Thelightfarm.com' has a section on coating emulsions.

[gandolfi]

I've been doing this for many years, and the link above (the "hake" brush) is a good choise.
important:in any case avoid any brushes that has metal in the handle (the cheapest ones...).
the metal can contaminate the emulsion.

also: be very careful with the mentioned calligraphy brushes, also mentioned. I don't want to say that colin isn't right, but in my experience, these brushes has a bad tendency to loose its hair.
I've seen images with "Fur" coating!! which isn't appealing!

Don't go cheap!

when used, the brush is cleaned with hot water only (rinse longer than you think!!) and let it dry with the brush (the hair) in the air, so to speak.
Don't let it dry, lying on a table. that way it takes much longer to dry, and the woodden handle and the string that holds the hair in place will be destroyed, and there will be "fur" again!

Any good quality of paper will do, as long as it can stand a long time in water...

watercolour paper is fine, but I like copper printing paper better.

I use a German brand most of the time, as it is cheap and with a very high quality...
I don't know, whether it is available at your place..

"Zerkall" 340grms copper printing paper.

have fun!
it is highly addictive!!

[Photo Engineer]

I'll have to add 2 comments here.

1. If the ferrule is brass, bronze, or zinc, there may be problems, but I have yet to find a brush with a metal ferrule that hurts an emulsion as long as you clean it and dry it after use. It is the corrosion that hurts!

2. Using a puddle pusher on paper causes problems. The paper swells at the point of contact and as you push it there is a swell differential down the length of the paper. You therefore get a "V" of denser imaging as the PP travels down the paper. The emulsion also spreads outside of the width of the PP and wastes a lot of emulsion.

So, the brush or a containment method is better. My coating blade, Denise Ross' coating device or spraying are other alternatives. If you must use a PP, fold up the edges of the paper to prevent loss over the edges, and coat with the emulsion at about 105 deg F and the paper cold. If it is hot, it buckles more and absorbs emulsion differently.

At a height of 0.005" (5 mils) the emulsion will spread at about 12 ml / square foot and give reasonable density to start with. You can go up or down from there.

I think this should be in the Emulsion Making and Coating forum as I don't think traditional silver halide is Alternative just yet.

PE

[Marco B]

I simply use a good quality very soft 5 cm wide modern nylon art brush (cost about $15, there not cheap unfortunately), as can be had in any good art shop. It has a stainless steel ring to hold the hairs, and I have never had issues with losing hairs from such a brush.

For paper, I have used acrylic art paper, which is very strong and holds up well during wet processing and doesn't absorb as much water as watercolour paper. It also seems to buckle less because of this.

Gandolfi: what is it you like about copper printing paper? I once tried it after having seen a similar comment by you before, but it seems to absorb water in a strange and strong manner, even releasing visible air bubbles if you drop it in a bucket of water, with audible(!) sound. It seems to hold many air cavities, to be very porous, and expel the air forcefully when it comes into contact with water... That can't be a good quality for a liquid emulsion paper, or did I have the wrong kind of paper?..

[Photo Engineer]

This propensity to entrap air and release it varies from batch to batch in the same kind of paper. I have several batches of COT320 that I coat on, and some really fizz up when I coat on them and others do not, or do not as much.

If the coating material (emulsion or sensitizer) is low enough in viscosity, then the bubbles fill in as they break.

PE

[nworth]

One method that was suggested for photofabrication resists (which are a quite a bit less viscous) was to hold the work horizontal, pour the required amount in the center, and tip the work from side to side until the work was evenly coated. Flexible work could be supported on a glass plate. Another method, which produces a smoother coating, is to place the work horizontally on a turntable, place the required amount of emulsion in the center, and whirl it at about 75 (78?) rpm until the work is properly coated. Of course you will lose some emulsion with this method, and it can be messy. Both these methods minimize bubbles. Of course, one of Ron's coating knives (or maybe even a cheaper, less accurate substitute) would be excellent.

[Photo Engineer]

The methods you describe cannot be used on paper. It is very useful on plastic and glass.

PE