Which parameter to change?

[luxikon]

I tested my first film today with following results: d = 0.2 @ I, d = 1.0 @ V and d = 2.12 @ VIII. I reckon the negatives a bit too dense and too contrasty. Which parameter shall I change, EI or developing time (or both)?
The film was Ilford SFX 200 (EI 200) developed in Perceptol (from scratch, 1+1, 18°C, 20 min, JOBO CPP2).

 

[ic-racer]

This method does not give you the slope (that is just checking Zone VIII for 'development time') and the Zone VIII will be changed with exposure. Basically get the exposure correct first. So underexpose some to bring Zone I down to 0.1 and keep development the same and see where you Zone VIII lies then.

Double check things also. Getting a d of 0.2 at Zone I when rating any film at its ISO speed seems a little high. Frequently they come out less than 0.1 at the 'box speed' unless you have a slow shutter or something.

 

[Neal]

Dear luxikon,

SFX as your first film test. I admire your courage. ;>)

Assuming you used a deep red (or darker) filter, you will have to start bracketing anyway. Many meters do not work as well with dark red filters as we might like. When using rotary development, I like to reduce advised times for development by 20% (as a first attempt) to account for the increased agitation.

Good luck,

Neal Wydra

 

[luxikon]

Dear Neal,

I'm not so bold as you think. I tested the strait film first. When I got that right, I go for the deep red filter.
Starting from Ilford's recommendations I calculated my 20 min. regarding temperature and rotation corrections. I'm going to follow ice-racer's advice and increase EI first.

Thanks
Klaus

 

[john_s]

I tested my first film today with following results: d = 0.2 @ I, d = 1.0 @ V and d = 2.12 @ VIII. I reckon the negatives a bit too dense and too contrasty. Which parameter shall I change, EI or developing time (or both)?
The film was Ilford SFX 200 (EI 200) developed in Perceptol (from scratch, 1+1, 18°C, 20 min, JOBO CPP2).

I'm not sure if your density figures are net of B+F.

 

[dancqu]

Which to Change

The obvious is development. Reduce development.
Way too much contrast. A reduction in development
will reduce your EI. At VIII 1.12 would be with in
reason Dan.

 

[luxikon]

@ john s
sure my density figures are net of B+F.

@ danqu
I'll try with 2 min reduction. Do you think that may be enough?

 

[2F/2F]

Way too much contrast to even consider it a start in calibrating the film, for use in normal pictorial applications, IMO. The way I see it, you shouldn't bother making EI adjustments at this point. Wait until you are a reasonable distance from "normal" contrast to tweak your EI, because the amount of contrast you put into a negative via development affects density even in the lower tones. At such high contrast, even your zone I placement can be affected. I'd chalk it up as a total loss and do the test again, doing everything the same as far as rating and your exposure sequence, but trying 10 minutes as a starting development time instead of 20.

P.S. It is not uncommon to have super contrasty negatives when first using a Jobo, if you are used to using a hand tank.

I must say that 20 minutes seems like a long time to be spinning in a Jobo...for any film and any developer (at least when normal contrast for testing is the aim). How did you arrive at this time?

It is also possible that you made a mistake in the mixing of the scratch developer, and/or perhaps a dilution mistake. Double check these factors as well.

 

[dancqu]

I'll second 2F/2F's recommendation.
Half the development time. Try for
a zone VIII of 1.20 give or take
some little. Then test for your
EI. Dan

 

[Chuck_P]

I tested my first film today with following results: d = 0.2 @ I, d = 1.0 @ V and d = 2.12 @ VIII. I reckon the negatives a bit too dense and too contrasty. Which parameter shall I change, EI or developing time (or both)?
The film was Ilford SFX 200 (EI 200) developed in Perceptol (from scratch, 1+1, 18°C, 20 min, JOBO CPP2).

Like has been said-----those density readings would produce a very steep curve. The film development chart at Ilford suggests for rotary processors to reduce the tank development time by as much as 15%. The tank development time for SFX200 in Perceptol 1+1 is 20min at 20 deg centigrade (68 deg F). The way I read it, you will need to back off 3 min from the tank time with the jobo---------17 min at 68 deg F should be the time used for testing your personal film speed, which would be a Zone I negative density of 0.9 to 1.1.

Assuming you are doing traditional ZS film tests, keep tweaking the EI by 1/3 stop increments while still using the time and temp as above until you get the Zone I density where you want it. Only when you have done that should you deviate from the manufacturer's recommended dev time to get a desired Zone VIII density that would then reflect your "N" dev time. Essentially, the Zone I density of 0.1 with your new EI acts like an achor point for the characteristic curve to pivot from as you hone in on your "normal" development time, which in traditional ZS terms would be a Zone VIII negative density of between 1.25-1.35.

Like 2F/2F said, the low end of the curve can "move" away from the desired Zone I density as various "plus" and "minus" times are found. I have found this true at +2 and -2 dev with d-76/tmx and you'll also find that fact discussed at some length in "The Negative".

 

[luxikon]

@ 2F/2F

Thanks, you are right. I forgot to dilute stock 1+1. Regarding developing time Ilford recommends 20 min at 20°C for SFX in Perceptol 1+1. I reduced time for rotation (20%) and extended for temperature according Ilford's graph.

 

[Ronald Moravec]

Adjust exposure to get the shadows right. Adjust time in developer to get highlights right.

 

[2F/2F]

Adjust exposure to get the shadows right. Adjust time in developer to get highlights right.

...assuming a fairly normal amount of contrast is achieved on initial testing, then yes. However, as the OP has told us, the developer was used at twice the intended strength, and contrast went through the roof as a result. As such, do what Mr. Moravec sez, but do it from the beginning again with the proper ratio of stock to water, not based off of the results of the first test.

 

[2F/2F]

@ 2F/2F

Thanks, you are right. I forgot to dilute stock 1+1. Regarding developing time Ilford recommends 20 min at 20°C for SFX in Perceptol 1+1. I reduced time for rotation (20%) and extended for temperature according Ilford's graph.

There ya go! Thanks for the explanation of the 20 minute time. Seems like the right time to start with (once you get the right dilution mixed, of course ).

 

[Anscojohn]

I tested my first film today with following results: d = 0.2 @ I, d = 1.0 @ V and d = 2.12 @ VIII. I reckon the negatives a bit too dense and too contrasty. Which parameter shall I change, EI or developing time (or both)?
The film was Ilford SFX 200 (EI 200) developed in Perceptol (from scratch, 1+1, 18°C, 20 min, JOBO CPP2).

*******
One at a time.

 

[nworth]

First, check the film data sheet to find out what the contrast should be. SFX is a specialized film, and I wouldn't be surprised if it was designed for somewhat higher contrast than normal films. In any case, it sounds like the contrast is high. The usual cure for that is to reduce the development time. Fifteen percent is a good starting figure. If the contrast is still too high, you can cut it again, or you can try a low contrast developer. Cutting the development time will eventually reduce your effective EI, but usually not by much. Bracketing is a good idea anyway, since normal exposure meters do not respond in a regular or sensible way to IR, which is quite variable. You can adjust your exposure after you get the contrast right, but keep bracketing anyway.

 

[luxikon]

I thank you all for your helpful advice. Perceptol 1+1 / 18°C / 20 min / rotation works fine as a starting point.

Klaus