Thursday, October 28, 2010

CuSO4 Bleach vs Flexicolor Bleach Test #1

Okay again... poor choice of shitty unbranded unknown 400 ISO old expired C-41 film leads to crappy results

Top is CuSO4, bottom is Flexicolor.

2min 45 sec in Flexicolor C-41 (38c), EI 50 (was intending +3 EI and N-2 dev.. not sure that worked out given the density)

This test though does prove Copper Sulphate Bleach WORKS, and the colour seems fine.

The density may seem similar overall, but each individual channel on the CuSO4 bleach is broader, though its a different image of course.

Anyway, density on both is so close to the end of the scanner range, that is normally clipped by 'max' levels, becomes hard to correct colour.

In any case, film is fogged, too much exposure also I guess for 2min 45sec.

But if the CuSO4 didn't work as a bleach, then there would also be a silver neg image on the film (which you could see by eye if there was), AND the density would be even greater, when max density is about the same as Flexicolor, differences due to exposure.

Other indications CuSO4 works: Back of film turns green/blue in bleach like its supposed, and you can see the image on the back of the film before fixing like it's supposed to as well.

Test needs to be re-done with fresh film, normal exposure and development.

But a big tick so far for CuSO4.

Bleach recipe used (I only mixed up 100mL in a beaker for a single frame):
100g/litre Copper Sulphate
100g/litre NaCl (I used table salt, whic his sea salt + anti caking agent since thats all I had - is fine).

You're supposed to filter or decant it as well, but I didn't.

According to literature I have, the shelf life is supposed to be 12 months or more (copper sulphate and salt aint going nowhere!), and the capacity is supposed to be 5 x 36exp 35mm rolls per litre (I'm sure it'd be more like other bleaches).

Bleaching time is alleged to be 6-7 min for film (C-41 and E-6) at 24 degrees celsius (I walked away and left both for 17 minutes as I forgot about them).

For paper (RA-4) its alleged 3-4 min at 24 celsius, and allegedly can do 30 8x10 prints a litre.

CuSO4 Bleach vs Flexicolor Bleach #1

C-41 1+9 Stand Test #1

Okay so basic test was, Flexicolor C-41, diluted in to 1+9, and about ~1.2mg/litre of potassium iodide added. A while back Daire Quinlan tried a C-41 1+9 stand development, I decided to expand the idea in the search for various ways for good quality processing of C-41 at 20 degrees celsius (harder than it sounds).

Processed at ~20 degrees celsius, for an hour, pure stand iirc.

I was going to adjust pH to put it around 10.2 or so, but then I thought stand development may have a compensating effect, which means the RGB densities shouldn't be too far off each other, and potassium iodide also is supposed to promote even layer development between layers.

I've included the original RGB histograms on top of the image so you can see the rough density for each channel, remember highlights to right on a histogram on negative films means denser, and to the left is thin.

The results are dense with a thin range, (dMax close to dMin for each channel), however, it's actually better than normal C-41 processing at 20 degrees celsius in this regard. Also some of the density may be attributed to the uneven developed areas which were denser as you can see (blown out or very bright as I corrected to the main part of the image).

But, with agitation it should prevent uneven development, but that density shall still... so the solution is shorter time... or  more potassium iodide, I think I will try more potassium iodide.

Another word on the density... it was very old no-name (unknown) brand 400 ISO film I got for 50 cents a roll at a fair, also overexposed, so there is base fog to it, so I feel dMin would be lower (good) with fresh film

Also grain is actually normal ocompared to regular proces C-41 with this film, where as Daire Quinlan experienced increased (excessive?) grain, may be a result of the potassium iodide I added, but it should be confirmed with fresh and good fine grained film.

Test #2 will increase the potassium iodide and increased agitation (probably at 20 minute and 40 minute marks), I am not sure how much to increase it by, perhaps 4x.

The goals are to get even development, a little less density, and much lower dMin.

C-41 1+9 Stand Development Test #1

Friday, October 22, 2010

Trying Rodinal Reversal / "E-6" Again.

Attempting Rodinal Reversals for colour film again... trying with C-41 first off for cheap testing to start with.

Specifically right now I'm half-way through a 1+100, 1 hour stand on some Supra 400 I had shot (probably random stuff) a while back to see how it turns out.

This time I have made additions of Potassium Iodide and Ilford Rapid Fixer (Ammonium Thiosulphate), I do have some sodium thiocyanate, which is typical in E-6 first developers, but I hope this is enough, or I'll try again with an increased amount.

Update: Nothing on that roll, will have to shoot another roll tomorrow for testng.

Update: Some advice from Photo Engineer of APUG - "Well, Ammonium Thiosulfate is not good. The Ammonium ion is also a fixing agent and fogging agent to some extent and should not be used in developers as a general rule. You should only use Sodium Thiosulfate in this instance or Sodium Thiocyanate. The Thiocyanate is often used but you will again have to work out the amount needed."

Sunday, October 10, 2010

Things to try

Been in Melb for 6 weeks now...

Got a few things to try... pull-processing C-41 film, which I've already done in Rodinal and re-developed to colour before.. though that was 14 stop pull... good for daytime long exposure with no filters.

Got some old ISO 400 film that seems a bit crap and foggy at 400... though I did accidentally overdevelop it. Anyway, expose it at EI 50 and develop for 2 min 45 sec is the plan to see how it comes out.

Some bigger pulls with shorter times or C-41 with a 1+1 or 1+2 dilution and EI 12 and slower just to have a play.

Need to find some HCl from a pool shop to finish my concentrated 2 part colour negative developer.

Also got a roll of Rollei Pan 25 to test out.. not sure what to actually use it on though is the problem.

I want to try some Ektar 100 in 35mm lab-developed, and developed 'normally' (EI 100) in my concentrated developer (1+1+50), and pulled to EI 25 (1+1+100), with 8000 dpi Flextight 848 scans - just to ascertain differences.

The unbranded 400 ISO C-41 film shot @ EI 400, developed 3 min 45 sec accidentally and not agitated much (2 stop accidental push, was very dense and crappy), developed in Kodak Flexicolor at home, colour corrected (since it's C-41, posting orange negatives would be kinda odd).