U of S | Mailing List Archive | alt-photo-process-l | RE: I SHALL NOT WANT...

RE: I SHALL NOT WANT...


  • To: alt-photo-process-l@usask.ca
  • Subject: RE: I SHALL NOT WANT...
  • From: Robert Hall <Robert@Roberthall.com>
  • Date: Fri, 16 Feb 2007 16:10:08 -0700
  • Comments: "alt-photo-process mailing list"
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Bob,

From whom did you purchase your chemicals?

Robert Hall
www.RobertHall.com

-----Original Message-----
From: BOB KISS [mailto:bobkiss@caribsurf.com] 
Sent: Friday, February 16, 2007 8:23 AM
To: alt-photo-process-l@usask.ca
Subject: I SHALL NOT WANT...

DEAR LIST,
	My kitty litter buckets runneth over!  At Eric's prodding I finally
bought a 55 lb bag of oxalic acid and a 50 lb bag of potassium carbonate,
the smallest quantities I could get over 1 lb at a time.  As they come in
flimsy bags I am storing them in old but clean kitty litter buckets with
tight lids.  Sooooooooooooo, I shall not want for Pot Ox PT/PD developer!
	However, here are some qualitative comparisons between paper (Cranes
Platinotype) coated and exposed exactly the same but developed in my former
favorite, sodium citrate dev, and the pot ox dev.  
	Same neg, coating chem same, re-humidification process same, dev
temp same 40 C, everything the same except the devs:
1) Pot ox gives more contrast.
2) Pot ox gives a little more speed.
3) Pot ox definitely gives a warmer print color.  
4) Pot ox compresses the shadows, i.e. they go to a solid black with less
separation even when highlight densities of prints in both devs match.  
*********Next, I will coat some paper, cut it into test strips, expose them
in my Nu-arc with the same step tablet, process them identically except for
the dev, read reflection densities with my X-Rite, and plot D-logE curves.
I will do a sample size of at least two for each option.  If there is,
indeed, a compression in the shadows, this should be obvious in the curves.

	I will report results when I (finally) get around to doing this.
		CHEERS!
			BOB