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dsphotog
20-Mar-2011, 02:02
Do wet plate process images produce a positive? If so how you make duplicate images?

I guess I need an overview of some of the options.
Thanks,
David Silva

Andrey Donchev
20-Mar-2011, 03:48
Hi David, the wet plate process, produces positive image if you shot on a blackened plate and negative if you shot on a transparent plate.

A.

Marek Warunkiewicz
20-Mar-2011, 04:33
Hi David.

It is always a negative process. What makes it a positive is the "paleness" or silver colour of the exposed, developed and fixed silver. When viewed against a black background (if the plate is glass) or if exposed on a piece of blackened (japanned) tin or the commonly used black trophy aluminium, it is seen as a positive. It's the same effect that you can see in a regular film black and white negative when it is a bit underexposed and viewed at a slight angle against a black background.

If you want to make duplicates, you can make your exposures on glass plates and then you can enlarge them onto traditional paper. Alternatively you can make the exposures on glass or tin (tin is easier to scan, I find), scan them and then contact print onto salted paper, platinum/palladium etc. You can also digitally inkjet the scanned image. There are many choices and you need to define what you want as a final image result.

Jim Noel
20-Mar-2011, 09:17
You need to go to the Collodion Forum where you will find more information than any one person can use.

dsphotog
20-Mar-2011, 11:50
Thanks!
I just signed up on Wet plate Collodion forum.
Wow, lotsa great stuff!

alex from holland
24-Mar-2011, 00:57
It's not always a negative process !!
You can produce positives and negatives.
When positive the lighter parts are show. No matter if you use black or transparent glass.
if you use transparent you have to blacken the back to see the complete picture.

I have a small movie showing the proces which can be found on my weblog

eddie
24-Mar-2011, 04:19
alex, they are negatives. that is why they are backwards when viewed on black or colored substrate. (tintype, alumitype, melanotype etc etc.)

a "positive" image on colored substrate is an underexposed negative. about 3 stops under exposed. (ie tintypes)

there are two options to make a true positive (where the writing shows up correctly....not backwards) you can scan the image and flip it OR you need to make a "regular" glass negative.

to make a "regular" negative you need to over expose the glass plate about 3 times more than if you are making tintypes. then the plate is used as any negative is used to print on light sensitive paper....and/or modern enlarging papers. they can be enlarged as well. they are just glass neg not the modern negatives we are all used to. it is possible to make alternate process images like VDB, Platinum palladium etc etc.

FYI. a tintype usually requires about 2-6 seconds depending on location and time of day....this time is for open shade. so you can see how challenging shooting a portrait as a neg would be....they would require 8-24 seconds in open shade.

i hope this helps.

eddie

alex from holland
24-Mar-2011, 10:01
Eddie,

when i look at a film "negative" it looks totally different form a wet plate negative.
Or am i mistaken now ? To me a negative has a totaly other look than a wet plate negative

alex