DIY Control Strips?

@Bill Burk will do! Thanks.

Bill Burk said:

The datasheet tells you specifically not to try to hit the 0.80 HD-LD, you are supposed to use the HD-LD that you get when you are happy with your negatives. So write down 0.72 as your aim and keep going your merry way.

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That's true, but at the same time, strangely, their listed time for FP4 in replenished DD at 24C and continuous agitation hits 0.80 exactly. I wouldn't necessarily expect the same for other developers which is probably why they say if you're happy with your negs, use whatever your HD-LD is and go from there.

I have dialed my Xtol-R times for HD-LD to be 0.8 and a sample FP4+ negative [1] developed in the same tank is much denser than my usual preference (and much denser than HP5+ shot of the same scene using datasheet time+temp). So in both developers my control strips appear to be somehow "less sensitive" than regular FP4+

[1] Medium-contrast scene metered with an incident meter.

McDiesel said:

I have dialed my Xtol-R times for HD-LD to be 0.8 and a sample FP4+ negative [1] developed in the same tank is much denser than my usual preference (and much denser than HP5+ shot of the same scene using datasheet time+temp). So in both developers my control strips appear to be somehow "less sensitive" than regular FP4+

[1] Medium-contrast scene metered with an incident meter.

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Or it could just be that 0.80 is more contrast than you prefer/are used to. If you were happy at 0.72, I'd just go with that. Lets not forget that LD is ~0.1 above FB+F and HD is most likely 1.3 exposure units up which would put 0.8 at ISO contrast (0.615) which isn't necessarily wrong, but it's generally more than what most people are accustomed to seeing. 0.72 would put it at ~0.55 contrast, which is a lot more in line with what many consider "normal".

Also, when you run your control strips, make sure you run it with the same minimum amount of developer per roll, or better yet, run it in an empty tank with just the control strip. I ran replenished XTOL before switching over to DD and one thing that I thought was my working solution bottle just being really variable, was actually me being inconsistent with how I checked the activity level via the control strip. Now (with DD, because that's what I'm currently using), I always run at least 300ml of working solution per roll when running a control strip, or even better, at the very beginning of a batch of black and white, I'll run a control strip by itself and modify either the working solution bottle with more replenisher (if activity is low), or the development temperature (if the activity level is high), then modify how much replenisher goes in after the run based on what the activity level was. If it was low, I already brought the activity level up, so I replenish as normal, but if it was high (almost never happens, it's usually either right on or low), then I trim down the amount of replenisher slightly, so the next run will be about right, or at least trending in the right direction.

@Adrian Bacon do you still have your old records for Xtol-R times for Ilford films? I am aware that you're running JOBO, and your times will be different, but I am interested in seeing how they compare to each other. In my case I run automated inversion agitation for 24C:

• HP5+ 8:00
• Delta 400 8:00
• Delta 100 9:00
• FP4+ 10:00
• Fomapan 100 ?

I wonder if you also needed more time for FP4+ vs Delta 100 (Xtol datasheet gives them same time for Xtol-R in rotary tubes), and also what was your Foma 100 time?

McDiesel said:

@Adrian Bacon do you still have your old records for Xtol-R times for Ilford films? I am aware that you're running JOBO, and your times will be different, but I am interested in seeing how they compare to each other. In my case I run automated inversion agitation for 24C:

• HP5+ 8:00
• Delta 400 8:00
• Delta 100 9:00
• FP4+ 10:00
• Fomapan 100 ?

I wonder if you also needed more time for FP4+ vs Delta 100 (Xtol datasheet gives them same time for Xtol-R in rotary tubes), and also what was your Foma 100 time?

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I'm sure I have them floating around somewhere, but I can't find them. I do have some of that information posted in the resources section with tone curves and a collection of times, but if it's not there, I don't know where it'd be. I switched over to DD about the same time my shop was burglarized, so it's possible my paper records where lost there, and I for the life of me can't find my electronic versions.

@Adrian Bacon that's how I found out about your setup - via the resources section, those posts show up nicely in Google searches. The reason for that ask is that Xtol datasheet doesn't match what I'm seeing: for Delta 400 it shows less time in Xtol-R than HP5+ but when an identically exposed shot is done on both films and developed in the same tank, I get more contrast with HP5+

McDiesel said:

@Adrian Bacon that's how I found out about your setup - via the resources section, those posts show up nicely in Google searches. The reason for that ask is that Xtol datasheet doesn't match what I'm seeing: for Delta 400 it shows less time in Xtol-R than HP5+ but when an identically exposed shot is done on both films and developed in the same tank, I get more contrast with HP5+

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Yeah, I don't know how Kodak came up with their times or if it's even the same contrast between emulsions. I know Ilford's times for DD are not the same contrast at all. It's almost as if they just get the minimum time needed to get 4 stops down from normal to 0.1 above film base plus fog at box speed and the resulting contrast is whatever it is, which sort of makes sense because if you're doing VC paper you can usually make it work, and if you're scanning, you can easily make it work as well.

Question for those using pre exposed BW control strips. Do the instructions ask one to plot the HD curve and obtain Contrast Index, or simply to compare each step to a list of values?

ic-racer said:

Question for those using pre exposed BW control strips. Do the instructions ask one to plot the HD curve and obtain Contrast Index, or simply to compare each step to a list of values?

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there is no H+D curve to plot. It’s 4 patches. dmin, ld, hd, and dmax.

Ok, so you just subtract the two to get the slope, with out physically plotting it. Seems pretty foolproof.

ic-racer said:

Ok, so you just subtract the two to get the slope, with out physically plotting it. Seems pretty foolproof.

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yes. They say dmin should be ~0.30, and HD-LD should be 0.8 plus or minus 0.06. They don’t give any guidance for dmax. It’s about as simple as it gets.