Re: Alkaline fixers and lumen prints


Cedric Muscat
 



Looks like the acid fix has better tonal rendition in the steps 7 - 21 range.


On Tue, 6 Apr 2021 at 19:31, Christina Z. Anderson <christinazanderson@...> wrote:
Dear All,

In 10 tests on 10 different papers some papers looked about the same with both alkaline and acid fix (and stabilizer). Many were slightly darker and slightly more reddish in tone with an acid fix aka Sprint. 

There was not one case where I preferred the alkaline fix or where the alkaline fixer should be required. 

But the real surprise was this paper which is either Bergger VCCM or Forte, can’t tell—two envelopes in one box unlabeled, but I will have a separate piece of each from their own packets this week to test. 

The alkaline fix is on the left and the acid on the right with such a marked color change. It may not show in this image but it’s a beautiful purple. 

How I conducted the test was one piece of paper with two step wedges on top, exposed all day sun, cut in half just before fixing, fixed in two separate trays for the same time.

It is probably not possible to make firm conclusions with all things lumen, but for me an alkaline fix is no longer. Two other people are also testing and we’ll see if this is consistent for them, too, so it’s not just me. 

I can’t discount that there is something else in Sprint that accounts for such a color difference.

The end.

Chris

Sprint Record Fixer
Ammonium Thiosulfate 80-90% 
Potassium Tetraborate Tetrahydrate <10% 
Potassium Borate <10% 
Potassium Acetate <10% 
Sodium Metaborate Dihydrate <3% 
Sodium Sulfite <2% 
Sodium Metabisulfite <2%



On Apr 1, 2021, at 9:19 AM, Christina Z. Anderson <christinazanderson@...> wrote:

Good morning!

(I am SO thrilled we can post pix).

I’ve been running a lot of lumen print tests to quantify some things, one of which is the use of an alkaline vs acid fixer to reduce fading of the colors.

I’ve done two tests now with an 8x10 Stouffers, exposed outside all day 9-6 full sun, print then cut in half, one fixed in Sprint (6 pH) and one in Formulary TF-4 (8 pH). The first time I did this I was very surprised to see a slight difference—a bit lighter color—in the alkaline fixed half.

So I did the test again and sure enough, same thing. Left is alkaline, right is acid.

I’m going to do a couple more of these on different papers but if it were based on these two tests alone I can’t support the theory of an alkaline fix reducing fading of colors. (Note: prints are still wet here and have not dried down to full darkness but the other test dried down was exactly the same, also different paper).

Has anyone else done this too? Does anyone have acid and alkaline fixes and can do a side by side? I’m going to use citric and sodium carbonate to “prime” the two fixes and do it again, too..both of the fixers I tested are ammonium thiosulfate with added ingredients.

I will measure densities with a densitometer to make sure it’s not just a color shift but an actual density dif, too.

Chris

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