Film Speed and Development Test (Excel spreadsheet supplied)
I don't believe in trial-and-error testing of film speed and development times, and manufacturer recommendations or the Massive Dev Chart cannot account for individual setups and darkroom techniques. Phil Davis' BTZS or the precise technique outlined in 'Way Beyond Monochrome' do a much better job. They are very similar to each other, using 5-6 rolls of film, an afternoon of work and one is done with it. No surprises, no future tweaking!
The problem with both methods is that they rely on a fairly laborious graphical data analysis. For BTZS users, software can be purchased, and I have been asked to generate something similar for 'Way Beyond Monochrome' users.
I'm glad to report that an Excel spreadsheet is now available to do this. The spreadsheet is free, and you don't need to own the book to use it.
You'll find it here:
I hope it helps and you will report back with any issues you may have, so, I can improve it for future use.
I have a question about your film test procedure. I use d-23 for my processing, 4 minutes is really low contrast for my processing, probably like n-3 or n-4. Does your spreadsheet have those development values baked in the calculations, or is it OK to use different processing times? Thanks for all your contributions.
Originally Posted by squinonescolon
The spreadsheet is flexible enough to deal with any development time sequence. Feel free to enter your sequence into cells G10:K10. It will even update the page titles on the other sheets.
The visual clues are:
yellow cells = feel free to enter your values
green cells = out put values, don't modify!
blue cells = optional, modify if you know what you're doing
Also, I'm using Open Office in the Mac and Linux, and this is what I get in the summary pane, is this correct?
Not quite. It should look as attached. I don't think Open Office does all the computations. I see some 'err' statement on your sheet. I'm afraid Excel is a must.
Originally Posted by squinonescolon
However, I see, you've used the .xlsx version. Try the .xls version and see if that works better in Open Office. No promises though!
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Is there a précis ?
There's a free BTZS spreadsheet available and its very much simpler to understand & does the same , a former APUG moderator was involved with the magazine article and the Excel spread sheet.
Many people no longer use Microsoft Office, the BTZS files work OK. with Open Office.
No dice. I'll get Office then.
Those are nice. Thanks for sharing.
Originally Posted by Ian Grant
There is no competition here. Use what you prefer, but the BTZS file does not do the same. It does not work with 31-step tablets and requires much more user interaction (more inputs), and I did not find it that easy to use.
With the WBM spreadsheet, you enter the data on the first page, enter the effective film speed on the last page, and you're done. You don't have to read anything off the graphs and enter it numerically (except for once). This relies on some matrix evaluation in Excel and is probably the reason that Open Office doesn't work with it, because it does support it. The final results are also not the same but very similar, except for film speed.
I was asked to do this, and I did. It is not a competition to BTZS. It's a different approach, but you are right, it needs more documentation.
I'm gonna give it crack on OO this evening and see what comes of it.
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