DIY Control Strips?

[NortheastPhotographic]

AFAIK you can't get any B&W control strips these days, which is nuts. How much could it cost to produce them? There are still plenty of labs who process thousands of feet of B&W film every day, but I digress...

I'd like to have a little more certainty with my XTol R solution. Does anyone have a good solution for DIY control strips? Would I need a sensitizer to expose a step wedge? Presumably I could also shoot a grey card using my Hy6 Mod 2, which is pretty much guaranteed to have an accurate shutter... But that seems like an imperfect solution as well.

 

[Lachlan Young]

AFAIK you can't get any B&W control strips these days, which is nuts. How much could it cost to produce them? There are still plenty of labs who process thousands of feet of B&W film every day, but I digress...

I'd like to have a little more certainty with my XTol R solution. Does anyone have a good solution for DIY control strips? Would I need a sensitizer to expose a step wedge? Presumably I could also shoot a grey card using my Hy6 Mod 2, which is pretty much guaranteed to have an accurate shutter... But that seems like an imperfect solution as well.

Ilford make them on FP4+ as far as I know, though they may be made to order. A calibrated step wedge would probably be the best place to start for making your own - and contact exposure to avoid camera/ lens flare.

 

[bernard_L]

Ilford provides/provided control strips for some of its films. Just now their web site seems to be in hibernation, following the coronavirus shutdown. I found this (an exampls):
https://www.ilfordphoto.com/amfile/file/download/file/249/product/592/
The price I remember was pretty high for amateur use.[I see Lachlan Young provided a similar, more concise reply while I was typing]

I've made my control strips, sort of, shooting a Kodak reflection gray scale (in the Kodak Professional Photoguide). Issues with specular reflection, accuracy of shutter speed, etc, requiring post-processing and self-consistency checks.

But your intended use, if I understand well, is more a consistency assurance check than a NIST-traceable sensitometry(!!).

I'd like to have a little more certainty with my XTol R solution.

I'd just shoot one roll of a gray (or white, does not matter) card, at ZV (which may or may not be the metered exposure, a recent discussion got me confused). Keep the exposed roll (120 if I judge from your reference to Hy6). For a check, unroll in the dark, cut off first the film trailer (judging from one of your regular developed films), cut off a couple inches (about one frame worth), slide into spiral, and develop. Compare density with similar test with known good, fresh developer. Then develop your precious images with confidence. With this method, you don't measure the speed point, nor the G-bar. But you know your current dev is as good as new (or not).
With 35mm I used a slightly different method. Working in the dark as required, I can cycle:

• cut out leader to half-width
• load film in dark
• do test exposures (one, two, three frames, depending on purpose)
• (dark) open camera, cut film in middle of "next" frame (still blank), store in opaque canister (metal)
• Iterate from first step until all film is used up, keep the strips for future use in the fridge.

Producing calibrated test strips requires to have accurate numbers for the actual shutter speeds, and for the T-numbers of your lens, and for the calibration of your lightmeter. And/or buy a sensitometer. And to wrap your head around some photometry.

 

[bernard_L]

Just quickly read through the document
ILFORD FP4FPC MANUALPROCESSCONTROLSTRIPS & FILMPROCESS CONTROL
and found support for what I wrote above, namely that process control is distinct from sensitometry. Nowhere is it stated what is the exposure of the patches LD and HD. Only what densities you should measure if the developer performance is nominal. This is in line with my suggested approach to establish a known good dataset using fresh film and fresh developer. And not worry about shutter speed, lux-seconds, etc...

 

[John Salim]

You cannot make highly accurate control strips with a camera !

Tetenal UK can supply to order Ilford FP4 Control Strips ( 35mm x 100ft roll ) at £110.77 + VAT
link here... https://www.tetenaluk.com/ilford-fp...-1-1672109?returnurl=/search?q=control+strips

I don't think Kodak manufactures TMAX B&W Control Strips 35mm x 5" ( 50 ) anymore - not seen any for a long time.

John S

 

[MattKing]

Try contacting Kodak Alaris: profilm@kodakalaris.com
Do you deal with a commercial supplier for processing supplies? They may have access to existing sources (if any).

 

[bnxvs]

And what's the point in such control strips? Many (not all) films change their properties over time. In addition, they are affected by the storage mode. So there is a high probability that no control strip will fully correspond to your films.
In addition, control strips are usually recommended to be processed no later than 12 hours, after their exposure. In this case time also affects the end result.
Industrial-made control strips made sense for the color process, but for black and white, I think it's best to just learn how to do it yourself once. You could read the book by Phil Davis "Beyond the zone system". He very simply explained forth this process.

 

[MattKing]

And what's the point in such control strips?

The OP runs a lab that processes film for others. Consistency of process is the point.

 

[Bill Burk]

https://www.photrio.com/forum/threads/enlarger-sensitometer.92518/

Here is my favorite thread about how to make your own sensitometer with a Stouffer scale and enlarger.

 

[Bill Burk]

And what's the point in such control strips? Many (not all) films change their properties over time. In addition, they are affected by the storage mode. So there is a high probability that no control strip will fully correspond to your films.
In addition, control strips are usually recommended to be processed no later than 12 hours, after their exposure. In this case time also affects the end result.
Industrial-made control strips made sense for the color process, but for black and white, I think it's best to just learn how to do it yourself once. You could read the book by Phil Davis "Beyond the zone system". He very simply explained forth this process.

Fred Newman basically uses an enlarger as a sensitometer. He sets up EV 2 at 0.4 seconds for 400 speed tests and EV 4 for 100 speed film. He uses Stouffer scale in a contact printing frame that he puts under his enlarger.

 

[Bill Burk]

By the way, one important measurement to track is pH. Are you keeping records of that? What are you using as a pH meter? (I haven’t tracked pH in my own processes since my glass probe broke, I eventually got rid of the broken meter).

 

[Adrian Bacon]

AFAIK you can't get any B&W control strips these days, which is nuts. How much could it cost to produce them? There are still plenty of labs who process thousands of feet of B&W film every day, but I digress...

I'd like to have a little more certainty with my XTol R solution. Does anyone have a good solution for DIY control strips? Would I need a sensitizer to expose a step wedge? Presumably I could also shoot a grey card using my Hy6 Mod 2, which is pretty much guaranteed to have an accurate shutter... But that seems like an imperfect solution as well.

Ilford makes FP4 control strips. You can order them from Roberts distributors. If you don’t have an account with them, it’s worth getting one. You’ll need your states business tax license info. Once you do that, you’ll receive a pricing spreadsheet with part numbers for everything you can order.

 

[cmacd123]

And what's the point in such control strips? Many (not all) films change their properties over time. In addition, they are affected by the storage mode.

Process control strips are normally provided refrigerated with a fairly short expiry date. The Lab will run one regularly on a schedule, and PLOT the density of the exposure. that will tell if the process is consistent, and if the Gamma is increasing or decreasing over time. the strips are consitant from roll to roll and alos often come with correction factors to transition from one roll to the next. (first strip from a new roll is also processed at the same time as one of the last strips from the old roll to confirm)

probably not much use for a hobby darkroom where everything else is done by hand. very useful for a pro lab where you don't want any surprises with customer film.

 

[McDiesel]

I recently started using Ilford's control strips based on FP4+ (ordered from Freestyle). It works quite well to keep my replenished Xtol activity on aim.

The only issue I have with it is that the densities I am seeing do not match the data sheet. The manual says that, when developed in ID-11 for 8:30 @20C the HD-LD density should be around 0.80. I am getting 0.72 on my calibrated densitometer, meanwhile the regular FP4+ negatives developed in the same tank as the control strips look absolutely gorgeous/normal. My agitation + temperature are perfect and consistent (TAS film processor with 0.02C thermometer). The agitation pattern matches Ilford's datasheets pretty closely, so this discrepancy annoys me. The only explanation is that maybe the 100ft roll of control strips is old, and Freestyle hasn't refrigerated it.

 

[Lachlan Young]

with 0.02C thermometer

Is this calibrated/ certified?

 

[John Salim]

Measure and compare the D-min of both a control strip and a fresh FP4 ( processed at the same time ).
As you know D-min will go denser over time and with poor storage.
John S

 

[radiant]

I would use sensitometer (or expose Stouffer strip with enlarger) to a fresh film and use it.

I built myself sensitometer from 3D printed parts, some led strip and microcontroller. Pretty simple to use and I assume would work fine with this kind of purpose.

 

[ic-racer]

It is nice to promote one’s commercial BW processing is standardized to Ilford’s specs, but if one is processing their own negatives, the development conditions would be determined by one’s enlarger or contact printing setup. Rather than the commercial control strip.
Also, sensitometers to make control strips were less than $50.

 

[Adrian Bacon]

I recently started using Ilford's control strips based on FP4+ (ordered from Freestyle). It works quite well to keep my replenished Xtol activity on aim.

The only issue I have with it is that the densities I am seeing do not match the data sheet. The manual says that, when developed in ID-11 for 8:30 @20C the HD-LD density should be around 0.80. I am getting 0.72 on my calibrated densitometer, meanwhile the regular FP4+ negatives developed in the same tank as the control strips look absolutely gorgeous/normal. My agitation + temperature are perfect and consistent (TAS film processor with 0.02C thermometer). The agitation pattern matches Ilford's datasheets pretty closely, so this discrepancy annoys me. The only explanation is that maybe the 100ft roll of control strips is old, and Freestyle hasn't refrigerated it.

is your 0.72 in xtol or ID-11? Are you sure your in-tank temperature is what you think it is? The developer temperature in the tank doesn’t always match the developer temperature before you pour it in, especially if there’s a difference in thr room temperature. Are you processing the control strip in the tank by itself, or with other rolls of film? If with other rolls of film, are you processing with at least 300ml of stock solution per roll (with ID-11)? I use those control strips with replenished DD and the results will vary depending on how much developer I have per roll.

 

[McDiesel]

@Adrian Bacon 0.72 is for ID-11. The in-tank temperature must be a tad higher than 20C because it measures 20.2C when I pour it out, probably due to ambient. The thermometer is traceable with a calibration certificate, this one. Shows 0C for freezing water and 36.6C for my body temp. Distilled water for everything. Two ideas come to mind:

• I may try matching Ilford's agitation perfectly using a Paterson tank: 20 seconds initial agitation, followed by 10 second of inversions every minute, as opposed to 30 seconds initial agitation followed by 3 inversions every minute which is my current TAS program. Those 3 inversions don't take 10 seconds, maybe this leads to less agitation overall...
• The 300ml of stock ID-11 is a "grey zone" point. I am using the smallest JOBO tank which takes 275ml, I may switch to a larger tank next time.

@ic-racer agreed, that's why I said this is merely an annoyance because I rarely develop film with ID-11, I just wanted to have a "reference point", since D76/ID-11 is widely seen as a "reference developer". My use of the control strips is to maintain Xtol-R activity: contrary to what I found searching Photrio archives, it is not as stable as Xtol-R fans claim it to be, so the amount of replenisher varies over time, probably caused by composition of emulsions / scenes and infrequent use. Prior to getting these strips I was using self-made "control strips" by exposing a grey scale + grey card under known lighting.

Thank you!

 

[Mr Bill]

The only issue I have with it is that the densities I am seeing do not match the data sheet. The manual says that, when developed in ID-11 for 8:30 @20C the HD-LD density should be around 0.80. I am getting 0.72 on my calibrated densitometer...

Hi, I don't know how Ilford gets their density aim values (for the control strips), but typically people using control strips would be using machine processors. I mean the sort that can do hi-volume processing vs something that takes a lot of manual work, loading reels, etc. This sort of machine processor would generally have more continuous agitation; a roller transport machine, as used in a one-hour lab would be one example.

What I am suggesting is that Ilford may be giving aim values for a continuous agitation machine, vs the interrupted sort of agitation generally used in hand tanks, etc.

Back when I was something of a youngster the place where I worked used to run several b&w process lines. What we'd do is to establish, through tests, a best processing condition for the film/printing situation. Then run a handful of b&w control strips to establish what they SHOULD look like when the process is what WE wanted it to look like. This would then become the aim for the control strips. It sounds like what you are essentially doing, so I think you're probably just fine.

Fwiw the work we were doing was all our own internal usage. Had we done processing for "outsiders," we probably would have established some better criteria for them, but that's not the sort of work we did.

 

[Adrian Bacon]

@Adrian Bacon 0.72 is for ID-11. The in-tank temperature must be a tad higher than 20C because it measures 20.2C when I pour it out, probably due to ambient. The thermometer is traceable with a calibration certificate, this one. Shows 0C for freezing water and 36.6C for my body temp. Distilled water for everything. Two ideas come to mind:

• I may try matching Ilford's agitation perfectly using a Paterson tank: 20 seconds initial agitation, followed by 10 second of inversions every minute, as opposed to 30 seconds initial agitation followed by 3 inversions every minute which is my current TAS program. Those 3 inversions don't take 10 seconds, maybe this leads to less agitation overall...
• The 300ml of stock ID-11 is a "grey zone" point. I am using the smallest JOBO tank which takes 275ml, I may switch to a larger tank next time.

@ic-racer agreed, that's why I said this is merely an annoyance because I rarely develop film with ID-11, I just wanted to have a "reference point", since D76/ID-11 is widely seen as a "reference developer". My use of the control strips is to maintain Xtol-R activity: contrary to what I found searching Photrio archives, it is not as stable as Xtol-R fans claim it to be, so the amount of replenisher varies over time, probably caused by composition of emulsions / scenes and infrequent use. Prior to getting these strips I was using self-made "control strips" by exposing a grey scale + grey card under known lighting.

Thank you!

If you're doing the control strip in D-76/ID-11 by itself with no other film, 275ml of stock solution is probably not the source of difference, but if it is with another roll of film, I'd recommend more stock solution, at least just to see if there's a difference so you can eliminate that as a potential source of discrepancy.

EDIT: Also, Bill has a good point, the published aim value might be for continuous agitation, not intermittent agitation.

 

[ic-racer]

@ic-racer agreed, that's why I said this is merely an annoyance because I rarely develop film with ID-11, I just wanted to have a "reference point", since D76/ID-11 is widely seen as a "reference developer". My use of the control strips is to maintain Xtol-R activity: contrary to what I found searching Photrio archives, it is not as stable as Xtol-R fans claim it to be, so the amount of replenisher varies over time, probably caused by composition of emulsions / scenes and infrequent use. Prior to getting these strips I was using self-made "control strips" by exposing a grey scale + grey card under known lighting.

Thank you!

I see, good point.

 

[McDiesel]

@Mr Bill good point, thank you. I think I'll just let it go, my working developer is Xtol-R anyway. I will just take my current FP4+ time for Xtol-R, develop the strips in it, write down the HD+LD values, and will keep them stable over time by varying the replenisher volume. Thank you everyone.

 

[Bill Burk]

I recently started using Ilford's control strips based on FP4+ (ordered from Freestyle). It works quite well to keep my replenished Xtol activity on aim.

The only issue I have with it is that the densities I am seeing do not match the data sheet. The manual says that, when developed in ID-11 for 8:30 @20C the HD-LD density should be around 0.80. I am getting 0.72 on my calibrated densitometer, meanwhile the regular FP4+ negatives developed in the same tank as the control strips look absolutely gorgeous/normal. My agitation + temperature are perfect and consistent (TAS film processor with 0.02C thermometer). The agitation pattern matches Ilford's datasheets pretty closely, so this discrepancy annoys me. The only explanation is that maybe the 100ft roll of control strips is old, and Freestyle hasn't refrigerated it.

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.