TINTYPE KIT EXPOSURE

[M P]

HELP!!!!
I am using the Rockland Colliod tintype kit in conjunction with pinhole cameras. I am exposing the plates in daylight within the cameras (no negatives). The pinhole aperture is f239. I've found a million charts that convert typical aperture exposures to the pinhole exposure, however, I don't know the speed of the ag-plus emulsion or how to convert that to an exposure time. Hypothetically, if the speed of the ag-plus were 10 ASA would my exposure be twice that metered for 100 ASA? How would I figure out what the speed is? Also, I read on the website that i need to meter with blue acetate in front of the meter because the emulsion only reacts to blue light... how much will that increase my exposure time... does anyone know if i'm looking at a 1/2 hour exposure or a 1/2 day exposure? I'd appreciate any input, I'm desperate for help. Thanks.
-MP

[Calamity Jane]

We had a discussion here a week or so back and, based on Rocklands recommended exposure of F16@.5 seconds, you are looking at an ASA around 2.

I started playing with Rocklands tintype last week and I WISH YOU LUCK!

The developer I got (direct from Rockland) is brown - which they say means it is "oxidized". Of a dozen plates with various thincknesses of emusion coating and exposures, I have only one image so far, and that is very dark - barely descernable on the black plate. Most seem to "wash off" in the developer.

I have e-mailed Rockland about the tea-coloured developer and should have a response tomorrow.

Since I had planned on doing "olde tyme" photography commercially this summer, I am (so far) singularly unimpressed with Rocklands tintype process!

[David F. Stein]

Calam. Maybe the folks at Photographer's Formulary can help you. They probably know how the process works and you could eventually substitute your own stock solutions.

[Christian Harkness]

Hi M.P. –

Here are a couple of thoughts on your questions. First of all IF the speed were 10 ISO [it seems that it is 2 iso] then 100 ISO would NOT be twice as fast. It goes like this, 10, 20, 40, 80, 160, etc………….

An iso of 2 combined with a pinhole camera makes for VERY long exposures – but………..

Secondly, if you use the reversal developer with the pinhole camera, you will get a negative. I assume you want a positive – you should use regular developer.

I am not on this forum. So, if you would like to contact me:

christianharkness@hotmail.com

Best wishes,

christian

[Ole Tjugen]

A little mental arithmetic... F/239 is about 8 stops down from f/16.

"Sunny 16" gives 1/2 second at f/16 for an ISO 2 film speed. That makes 128 seconds at f/256 (close enough to 239). 128 seconds is about 2 minutes. Add reciprocity failure, and guess at 5 minutes for a first attempt?

[Christian Harkness]

What was I thinking????? - Sorry about that negative positive comment above which is all wrong. Of course you will get a positive if you use the reversal developer! Grrrrrrrrrrrr......

[Elgin_tinty[es]

Hello,
I am using the Tintype kit with AG Plus Emulsion since about a year.
I use a 19th century camera. Full bright sun f stop 16 (Bausch and Lomb shutter 1892). 1/2 second.
The only problem I have are bubbles on the plate, when I pure the soultion on my
plates. And sometimes the pictures peal of the plate.

Kind regards
Elgin

[Kaden Kratzer]

What's a Rockland Colliod tintype kit?

I use in general the same method and materials/formula as the Ostermans'.

http://www.collodion.org/

[Bruce Schultz]

Stay with the Osterman material. Rockland is an inferior, unauthentic substitution.

[mercboyan]

I know this forum is rather old, but I am new here, so forgive me.
I use the Rockaloid Tintype kits and I find they work great! I am doing a very different process than most, but I use the jappaned plates and emulsion from Rockaloid as well as the reversal developer kit.

You can see my Ferrotypes here:
http://sites.google.com/site/mercboyanferrotypes/home/ferrotypes-gallery

I recommend taking a white or silver Sharpe marker and drawing a big X on the back of the plates the second you get them. It will help keep you from accidentally pouring the back of the plate (which will cause the image to slide off in the developer).