Ralph Lambrect's Film Testing Spreadsheet
..............has anyone ever used it? I finished tests with 4x5 TXP in HC-110 (1:63) at 68 deg F. I don't like the results, not attributing anything to the spreadsheet, but something I did I'm sure, but not sure what that is. I did not use a 6th sheet for film speed as I'm not sure how the actual film speed test is recommended by Ralph, I haven't got his book yet. I input a speed consistent with his statistical typical speed of 2/3 less box speed.
The spread between the 4 min avg gradient and the 16 min avg gradient seems quite narrow to me, resulting in such a narrow range of development times from just below "N" to just below +2. This, I certainly did not expect as I was hoping for clear +2 to -2 dev times. I developed in the Combi-Plan tank, using inversion agitation cycle of 4/10/1--------4 inversions in 10 sec every 1 minute, there was no temperature drift, processing is very consistent. In the .xls attachments (hope you can view them) are the TXP test that I finished recently using the 4, 5.5, 8,11, and 16 min times and a TMX (x-tol 1+1) test I did last year, but before having this spreadsheet, the times are my own determined from testing as described here, I simply input the densities into the spreadsheet from those development times. The X-Tol results are much more normal to me, a difference obviously being it was with a 100 ISO film versus an ISO 320 film with TXP.
So, this test with TXP seems strange to me, and I exposed the step tablet the same in both tests i.e., a Zone X exposure. But, one difference may be that I used a middle gray test target in the X-Tol test and a white test target in the TXP test, I don't see why that should matter. The TXP test results simply do not look right. I welcome any thoughts.............especially Ralph's.
Last edited by CPorter; 06-13-2012 at 07:22 AM. Click to view previous post history.
I would imagine Ralph has used it.
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.
Originally Posted by lxdude
that guys knows his shit, and I'm sure he'll chime in here.
In 4 min HC-110 (1+63 AKA Dilution H) your raw data shows you get 1.0 NDR over 8 stops.
That's "N-1" the way I work.
It is not a huge difference that the spreadsheet calls this "N-0.4" (If I read the formula correctly Ralph uses the constants 1.2 NDR over 7 stops to define "N").
Relatively speaking, I think you are getting more development activity than you might want... since you got a lot of density in 4 minutes.
If development results are even, then there you have it: You have a rapid process. If you are getting uneven results, then you might pick XTOL for any film you mark for "N-1" or less development.
p.s. I work for Kodak but the opinions and positions I take are my own and not necessarily those of EKC.
give me a day or two to look at your data. i've used or helped people use the spreadsheet in over 50 cases and it worked well every time!
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I have used Ralph's spreadsheets a lot. Spreadsheet has always gave same or almost same CI values as my previous paper calculations and measurements including BTZS's and WBM's rulers (and calculations). When there have been noticeable difference, it's usually caused by selected location of the speed point (I used 0.1 earlier) and used VIII's target density. If the curve isn't linear, these may introduce lot of variation.
In case of low contrast results like in old picture above (curves for 4, 5.5 and 8 minutes), the measured curve won't reach VIII density.
Where to get right CI? One may extract it from the measured part of the curve, one may extend the curve by approximating the shape etc.. If the low contrast curve shape is upswept, CI calculation may vary a lot. Unless test is done by extending test target's range with ND filter or with two exposure (of step wedge).
I think I was wrong about the HC-110 being overactive. I now think it is just about right.
I graphed this on paper and overlaid a transparent Contrast Index meter.
It was difficult to find the Base + Fog point to zero the meter, so I fudged by moving it up.
When I fudged the zero, I came out with CI's:
4 Min > CI 0.4
5.5 Min > CI 0.45
8 Min > CI 0.5
11 Min > CI 0.6
16 Min > CI 0.7
For a 1.0 LER, this set came very close to being:
4 Min > N-2
5.5 Min > N-1
8 Min > N
11 Min > N+1
16 Min > N+2
When input my CI as average gradients in blue cells of Ralph's spreadsheet:
4 Min > N-3
5.5 Min > N-2
8 Min > N-1
11 Min > N
16 Min > N+1
1) You expected and got very clear N-2 to N+2.
2) The data points are hard to fit to curves.
Well, thanks Bill, but what am I missing here? Why are you using a LER or LogH of 1.0 to make these points, not that I don't appreciate them , but the sheet specifies 2.1. So, just considering what the sheet is telling me with my data, I don't have clear +2 to -2 dev times. I guess I don't follow you.
Originally Posted by Bill Burk
I should probably state that I am not really interested in the average gradient results of the spread sheet, just the "N" dev times and the associated effective film speeds. I adjust the gradients as Ralph suggests to tweak the curves as needed.
Originally Posted by Bill Burk
Did you mean to say a NDR of 1.2 over over about 8 stops. I see the LogH range of 2.23 (7 1/2 stops) presented in the 4 min results of the "Curve 1" tab. By raw data do you mean the "Input Data" tab? In which case I see the 4 min density range of 1.05 in a LogH range generated from the tablet of 1.95 (6.5 stops). Just curious about your reference to a NDR of 1.0. Like I said, I must be missing something.
I think this picture will be better than a thousand words...
CPorter HC110 Chart
Exposure (the step wedge) goes horizontally 2.1
This makes "N" 7 whole stops which fits the Zone System.
Negative Density Range goes vertically.
I use 1.0 for personal reasons to hit between Grade 2 and 3 Galerie.
Ralph goes for 1.2 and that is fine. I drew them both
The curves are accurate. But I was very hasty drawing the marks "NDR 1.2" ... "NDR 1.0" and "N+, N, N-" - I just wanted to see approximately where the "N" was falling.
It's without flare, to keep it simple.
When I take my densitometer measurements, I measure and note Base + Fog for each sheet. Then I Zero the densitometer on Base + Fog for each sheet and all my measurements are "above B+F". It may help us if you describe how you zeroed the densitometer or kept tabs on Base + Fog.