Basic cyanotype advice needed please...

[vickersdc]

Well I tried coating some of my home made paper today and exposing under my new (to me) UV light, but the paper just disintegrated during the wash. I´ve now just coated the remaining sheets in gelatin / chrom alum to further size them. I also thought I´d give cyanotype on glass another go, and I also sized some zinc sheet too as I fancied trying cyanotype on to metal.

[vickersdc]

As expected, the cyanotype on glass only left a very faint image - I never could get a decent cyanotype on glass! I can't work out if I need a thicker coating of gelatin, or multiple coatings of cyanotype.

As for the metal, well here's the image...


http://farm6.static.flickr.com/5250/5254265268_90c0a762db.jpg

This was a zinc sheet, coating it with an acrylic gesso then a traditional cyanotype mix (with added citric acid). That yellow on the image is the solution that I just couldn't wash it - it really wouldn't shift, so it'll be interesting to see what will happen over the next few weeks / months...

I note that gesso is also alkaline and that's probably not ideal for cyanotype permanence, and I've just coated some glass and more zinc plates with it (using a glass rod to give a smoother surface). As I've still got some gelatin made up from last night, I might just overcoat the gesso with gelatin once it has properly dried.

[R Shaffer]

Well I tried coating some of my home made paper today and exposing under my new (to me) UV light, but the paper just disintegrated during the wash. I´ve now just coated the remaining sheets in gelatin / chrom alum to further size them. I also thought I´d give cyanotype on glass another go, and I also sized some zinc sheet too as I fancied trying cyanotype on to metal.

If the additional sizing does not work, have you considered mounting the paper to one of your zinc sheets?

Either way, looks like fun.

[Hexavalent]

Well I tried coating some of my home made paper today and exposing under my new (to me) UV light, but the paper just disintegrated during the wash. I´ve now just coated the remaining sheets in gelatin / chrom alum to further size them. I also thought I´d give cyanotype on glass another go, and I also sized some zinc sheet too as I fancied trying cyanotype on to metal.

Does your "home made paper" incorporate internal sizing? AKD helps to bind the fibers and lend a little more wet-strength. It should be incorporated in the wet-end for best results.

My preference is for gelatin hardened w/aldehyde - no staining, no residual salts, and very little swelling.

[vickersdc]

My paper has no internal sizing - originally I had added the arrowroot for that purpose, but it quite clearly made no difference! Anyway, I'm pleased to report that a couple of smaller pieces (that had been arrowroot'ed), had the gelatin / chrom alum size added (dipped into the solution). I then exposed these as normal and started to wash them. Then I ran out of time, so I left them in a slightly acidulated water bath for about 4 hours! They were fine, actually it was really handy as I was having trouble clearing all the solution out :)

Hopefully this week I'll get a chance to put the gelatin over the gesso (on the zinc sheets and the glass) and see how that goes.

Thank you for your replies.
David.

[vickersdc]

I've now done the gelatin and gesso thing, and had a mixed result (most likely due to my own inability to wait the required amount of time!).

Using the glass rod for the gesso was, even if I say so myself, a moment of pure genius ;) The final image looks loads better for not having all those brush strokes running through it!


I mixed up a gelatin / chrom alum solution and coated the gesso & zinc sheet. This did almost completely eliminate the problem with the gesso wrinkling up when put into water (I washed the image in a small plastic food tray). The image washed out quickly too - nothing like as long as I did when just using gesso. Unfortunately for me, I didn't wait a full 24(?) hours to allow the gelatin to harden and one patch did wash off :(

I'll wait a bit longer until I do the remaining zinc sheet and glass plates! Overall though, I'm rather pleased with this attempt, despite it's obvious imperfections, and I hope the gelatin will act to buffer the cyanotype from the alkaline gesso.