Joao
Negativistic forever
Hello
I am currently ressuscitating an old Durst 606 enlarger, and now I need to ascertain that the light reaching the paper is homogeneous, I mean, that it has the same intensity in all the exposed paper. What is the best way to do this? Will a exposure meter (enlarger meter) be enough for this purpose? Any other way? Thanks in advance for your sugestions.
best regards
Joao
I am currently ressuscitating an old Durst 606 enlarger, and now I need to ascertain that the light reaching the paper is homogeneous, I mean, that it has the same intensity in all the exposed paper. What is the best way to do this? Will a exposure meter (enlarger meter) be enough for this purpose? Any other way? Thanks in advance for your sugestions.
best regards
Joao
Roger Hicks
Veteran
Dear Joao,
'Waste' a sheet of paper exposed to give a light grey (no film in the carrier -- or a piece of tracing paper if you want a longer exposure.
Or put 5 pieces of smaller paper on the baseboard; develop all five to completion.
Bear in mind that some vignetting is normal.
Cheers,
R.
'Waste' a sheet of paper exposed to give a light grey (no film in the carrier -- or a piece of tracing paper if you want a longer exposure.
Or put 5 pieces of smaller paper on the baseboard; develop all five to completion.
Bear in mind that some vignetting is normal.
Cheers,
R.
Joao
Negativistic forever
Thanks, I supposed that a grey negative (or someting like that) was needed (see my previous post). I will give it a try - and maybe I could use my money in something other than an exposure meter...
Best regards
Joao
Roger Hicks
Veteran
Dear Joao,
Bear in mind that the eye is a VERY good comparator, so you should be able to 'eyeball' the most even illumination if (as with most enlargers with movable bulbs) you can move the bulb while it is on.
Then test it as suggested.
Cheers,
R.
Bear in mind that the eye is a VERY good comparator, so you should be able to 'eyeball' the most even illumination if (as with most enlargers with movable bulbs) you can move the bulb while it is on.
Then test it as suggested.
Cheers,
R.
Nicholas O. Lindan
Newbie
Well, yes and no. If the areas are adjacent with a clear demarcation between the areas then they eye can see small differences.
But, if the areas being compared are separated then the eye is easily led astray:
http://web.mit.edu/persci/people/adelson/checkershadow_illusion.html
The eye (my eye, at the least) can't reliably sense 1/2 a stop of fall-off on an enlarging easel.
--
Nicholas O. Lindan
Darkroom Automation
Last edited:
maddoc
... likes film again.
Interesting thread ! I just recently started wet-printing again (using an old Durst M601, with both condensor and CLS66 color-head) and asked myself the same question: How to adjust the bulb (when using the condensor) to get really homogeneous illumination ?
titrisol
Bottom Feeder
Get an Ilford EM10, excellent enlarging light meter.
You can assert differences of 1/4 stop
You can assert differences of 1/4 stop
maddoc
... likes film again.
Just started looking for one !Nicholas O. Lindan
Newbie
1/4 of a stop is 1/2 of a Zone-system zone/tone when it comes to paper. You may find you want to be able to measure evenness of illumination to a finer degree.
Last edited: