Van Dyke chemistry

[damon_vrettos1]

I've just started with the Vandyke process, and have some problems.

When I expose the paper under my ultraviolet bank of lights, the dark

areas don't ever get beyond that of what the midtone should look

like. Even if I leave it there for an hour, it never reaches an

acceptable density. Also, with contrasty negs., the images are

extremely low contrast and muddy. Could my chemistry be

contaminated? Here's the two things I did that might cause it. I

measured the chemistry with a metal spoon, and I used tap water

instead of distilled water.

Any advice would be invaluable!

 

Damon

[christian_harkness]

Damon, I only have experience with Van Dyke exposed by sunlight, and generally have no problems. I used tap water to mix my chemistry, but then, tap water can vary so widely - one never knows. I did have problems using different kinds of paper though. My favorite/standard is Arches cp. I use it for Van Dykes, Cyanotypes, and printmaking, but because of its rough texture, not everybody likes it. <P>

 

In short the one thing I would advise is try different papers, also, if possible, try the sun.

[damon_vrettos1]

Thanks for the input Christian. I've tried 7 different types of watercolor paper, and used the sun as well. It just doesn't "get there" as far as density or exposure. I'm thinking now it's the chemistry....

[christian_harkness]

Sounds reasonable. I use the chemistry from Photographers Forumlary & basically never had any failures, except with the paper. I am not particularly neat or orderly - so, don't give up!!!

[christian_harkness]

Hi Damon - here is one of my average VD prints. Its about 6x9 inches on Arches cp.<div></div>

[smieglitz]

Hello Damon,

 

Most of my VDBs print in 3-5 minutes with UV tubes about 6 inches from the frame. I suspect the negatives are at fault if you are sure you have mixed the chemicals correctly. Are you using standard film negatives and do you know the density range? Some digital negative substrates block a significant amount of UV (as does some special glass/plastic which may be in your contact frame).

 

Try double- or triple-coating the emulsion. (Let dry fully between coats.) This will add density.

 

Also, the VDB image is very susceptible to bleaching in fixers that are too strong. Use a plain sodium thiosulphate solution ("hypo") at 2% strength. Rapid fixers will bleach the image and give the low contrast weak results you describe. Be aware that Kodak Rapid Selenium Toner is about 40% rapid fixer/ammonium thiosulphate so selenium toner will also severely bleach the image. The proper fixer will immediately shift the image from a weak , underexposed , mustard-yellow appearance to a stronger red-brown image when the print is put into the fixer solution. Is this happening with your prints?

 

There is a very good section on printing VDBs on the "unblinking eye" internet site. Check it out. (Sorry, I don't have the URL handy but Googling should turn it up.)

 

Hope something here is helpful.

[joe_tait1]

Hi Damon.

 

To really answer the question, you have to supply a lot more information.

 

1) What kind of negatives are you using? What is the density of the negatives?

 

2) What VDB formula, how long are you exposing after coating? How old is the VBD solution?

 

3) What kind of UV light setup do you have? How far away is the print from the lights?

 

Generally speaking, low contrast and muddy prints are caused by a negative with too LOW density. I shoot for 1.8 on most VDB I do. If the dark areas aren't exposing to dmax, perhaps the print isn't close enough to the light. On my setup (48" BLB 30 watt) the print is 2-3" from the lights and I expose for 4-9 minutes. Have you tried exposing a clear piece of film or just the print to UV and print test strips to detemrine dmax time?

 

Now the tap water....definite no-no. The silver nitrate can precipitate out of solution with tap water. Never mix solutions with tap water. Some might say they do fine, and I am not saying they aren't, but tap water is quite variable and causes a lot of problems in photography generally, moreso in alt! BTW, I have even bought cheap distilled water and seen the silver nitrate precipitate out. Curiously though, the prints look fine!

 

-Joe