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Historical photographic methods in use today – the art, processes and techniques of alternative photography

Can anyone tell me why, even after an hour exposure in full sun, my gum print just flushes down the drain? I am using a variety of papers, most lately Rives BFK which I size with gelatine hardened by an alum soak, then a good long rinse. My solution is 10ml gum bichromate, 10 ml saturated potassium bichromate solution and 1.5 grams lampblack water color (I use Grumbacher). I am exposing thru a paper negative made on my inkjet printer, the paper is vellum of the kind used for drafting. I soak in 70 degree water. Usually an image appears in the first few minutes, then just diffuses off the paper into the water. Even the last print, which I exposed to sunlight for an hour eventually washed away. What am I doing wrong? Can anybody give me some insights? Thanks! Bruce

Could be that UV is not penetrating your paper neg the way you think it should be...I use overhead transparentcy on my inkjet for negs. I use what ever brand I can find... I have tried the OHP that everyone raves about but for some reason...I'm just not happy with it. for one thing, tape sticks to it terribly.

I use a very similar formula...although I did switch from lamp black to Paynes grey... finer pigment and I like the tone of it better. Kind of neurtalized the warmth of the dichromate yellowness.

I have some of my prints posted on my personal web page
http://home.earthlink.net/~tseabright/

Good luck and let us see what developes!
Crystal

Sorry, having a blonde moment. I ment to say that I get a image in about 30 seconds exposing in mid day sun in So Cal. with a similar formula.

Have you run test sequences of 30 second intervals with NO neg for a few minutes to see if you are getting an active emulsion?

I know when I did some VDykes with paper negs, it took FOREVER to expose them.
Crystal

Thanks for the imput, Crystal. I am probably not getting sufficient UV transmission thru my negs, since even cyanotypes need a good 20+ minutes to expose properly. There may also be significant UV loss thru the glass in the print frame. I'll take your advice and run some tests and switch to transparency film for the negs. What wonderful work you do (I checked out your website). The image of the peiwinkles especially intrigued me. Was it accomplished using color separation negs? Thanks again!

Thanks Bruce..yes separations made on PS CS. 20 layers of emussion at 5:1 printed out in the sun.

How THICK is your paper??? I found that anything over the 140 gsm range is too thick for alt processes. I use 140 gsm (on the thinnish side) with no problems.

Also -- try increasing your dichromate to 12.5 ml & see if that helps.

And how thick is your glass???? It would have to be awfully thick to really cut the uv, unless you've gotten ahold of some uv-resistant glass (it's usually the matte finish type of glass)

Bruce, how did things work out with your printing? Any luck?

Had a great week in Toronto. Shot lots of fruit stands and markets...Cant wait to print. but the sun isn't out today.

Thanks for the info everyone! I am still experiencing problems--I am using several papers up to 140#, and I switched to making negatives on clear inkjet transparency stock. I can now get a very faint image if I expose for 30 minutes or longer in mid-day sun (BTW Iam in south central Indiana--no shortage of sunshine this summer!). The glass I am using came with the print frame, manufactured by and purchased from Photographers Formulary. I assume they would not use glass that is problematic. I am going to try increasing the dichromate to the max. Another possibility may be that the days I have printed have been VERY hot and the paper inside the frame heated up during the exposure. I wonder if this could have a bearing on my results. I have made a few passable casein prints with my system, so I think there is enough UV getting through (I also have made some good cyanotypes with the print frame and clear negs)
I'll keep you all posted! Bruce

I read in Dan Burkholders book about oiling negs paper negs to improve transparency.... just a thought. Not that it matters if you've switched to transparency.

How about your water source??? you using distilled? or from the tap? Something just doesn't seem right still. It's got me puzzeled.

I thought of something that can cause your image to not stick well,....How much size did you have on that paper? what kind was it and what is the paper type...