I understand the instructions on the chart (took a few minutes) but I am not really sure how the two readings can relate directly to an indicated paper grade. Am I right in assuming that this givea a suggested grade and your experience with these readings will eventually result in a more personalized graph?
Understand you are dealing with a man who has up to this point been a seat-of-the-pants sort of darkroom worker. I have never used a densitometer and don't totally understand Phil Davis so that may be the problem.
The numbers given by the graph are a good starting point.
The way I see, paper is the most expensive consumable of B&W photo (and probably color, too), so, any means of avoiding paper waste will pay itself very quickly.
First, I did make test strips so with the EM10 dial at 90 (it could be 80 or 100, 90 was the center) and reading the darkest area of interest in the negative (not a burned highlight, something zone users could call zone 8 or 9) I had the corresponding exposure time (in my case, using fixed grade paper it was 3 seconds).
This calibration shall be done for all types of papers you use, determine each one's corresponding exposure time and using filters if VC (for instance, using Ilford filters grades 4 to 5 requires double exposure time), write it all down so you will not forget.
This in my limited experience was very repetitive - you adjust the lens aperture so the green led lits and expose for this calibrated time and highlights in the paper are very similar from one neg to the other (note: this reading may be slow, so wait some seconds before final light adjustment and turn off safelight).
Then using the EM10 to measure an light area of the neg - shadow with detail, like zone 2 in the print - you estimate the paper grade necessary from the graph.
This last part was not very precise, I still do not know if due to the graph not beeing precise or simply due to a matter of my personal taste.
But for sure the graph suggests grade 3 to this neg, 2 to this other one, etc.
For my eyes, the suggestions were less contrasty than I like - the jury is still out since it wasn't a simple matter of say adding 1 grade to all readings.
Well maybe it's simply that the photographer is expected to do its part...
I hope the above text makes sense.
The point is htat by measuring shadows against a standardized highlihgt exposure, you establish a denity range for the negative. The graph then suggests a paper grade that will allow that density range to be printed on the paper in one exposure.
With a little bit of mental gymnastics, it can even be adapted for split grade printing! Paper and pencil would probably be safer, but they tend to get lost in the dark...
So I do all these measurements, then mentally add a bit with that filter, burn in a bit here, dodge a bit there...
And I'm supposed to be a scientist?
-- Ole Tjugen, Luddite Elitist
And Nobel prize level
Thanks guys. After thinking about the chart over night and with what you just wrote it makes perfect sense. I can see using it to help evaluate the neg and maybe "save a tree". It just gives a little more objective measurement than my usual "hmmm this neg looks a little flat, maybe I should use a 4 filter".
No one would ever accuse me of being scientific in the darkroom but with the way they hand out Nobels I might get one anyway.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
Just a quick, silly note:
The factory calibration number for the EM-10 corresponds to 0,5 lumens.
A more serious one:
I did a silly thing by developing TMX in Diafine.
Too long a history to post again.
The lousiest, contraty negs I ever had.
The EM-10 suggested paper grade 1 or less.
Righ on spot.
I recently purchased an EM10 (eBay ú1) and tried the method used in the hyperlink above but with poor results.
Originally Posted by Jorge Oliveira
My method was as follows
1. measure a highlight with grade 2 filter in place and calibrate aperture to read 90 on dial.
2. measure a shadow and read the guage.
3. determine grade from graph using 1 and 2 above
The main problem was using the 9s predicted exposure was way of the mark. I required times of 20 secs minimum. Was I doing this wrong (should the filter be on? Or is the calibration out?) Any comments or other ways of using this baby
The safelight was off during measurements
Last edited by philldresser; 11-15-2004 at 03:49 PM. Click to view previous post history.
Reason: Poor ytping :)
It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.
Ole-sorry to barge in on the thread but could you PLEASE post some results on the Bergger contact paper?. It's not really available here so would like to know
If the contrast was right after correcting the time the technique worked, you just need to calibrate to the paper speed. These methods really are just guideposts, once you get started with it take note of any deviations and corrections needed so you can apply them anytime you use that particular paper/developer/enlarger combo.
Originally Posted by philldresser