Development by inspection

I have some Ilford Ortho sheet film which I am planning to tray develop by inspection, using a low-power red safelight. Does anyone have any experience of this process? How do I assess the right moment when the film is correctly developed?

Bill

Bill Banks said:

How do I assess the right moment when the film is correctly developed?

Bill

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Practice.


While Ortho is red safe, I'd use the standard of using green as the safe light. Green is the choice as our eyes are most sensitive. To learn you should take a know good exposure and develop by time . Look at the neg about 10% before time, at the scheduled time and about 10% beyond normal time so you can learn to judge. DBI take patience and practice so you do not want to try it on something important.

TR

Use a red light!

While green is right in the middle of the eye's sensitivity, red (a) won't fog the film, and (b) won't affect night vision.

Look at the BACK of the negative. The emulsion side should look almost entirely black, and the back side should just start showing some details.

Then asses the negative after completing processing, and adjust your definition of "just start showing some details" for the next negative. Repeat until skilled.

I've used a lot of the Ilford Ortho film you need to take great deal of care what safelight you use as it's quite fast and sensitive compared to ortho line films etc.

Ian

Ilford's Ortho + qualifies as a fast orthochromatic material. A deep red safelight, equivalent to Kodak's #2 safelight is the recommended safelight for this material and it is safe. You can load your film holders in this light, and you can tray process by inspection as well. It is a lot more dim than "normal" safelight conditions

The film is sensitive to green light, just like any other panchromatic or orthochromatic film, so I'd be leery of using the #3 green safe light. In any case, the green #3 safe light can only be used AFTER development is at least 50% complete and then for only a few seconds. It needs to be so dim as to make it virtually useless for anything more than orienting yourself in the darkroom. With a little practice, you can do this by touch.

Read this document for data on all sorts of safelights and their applications. The document comes complete with charts outlining the spectral output of each filter. Compare the spectral sensitivity of the material you'll be working with against the spectral output of the safelight, and you'll know exactly what will work and what will not.

You might also want to consult this document, "How Safe is Your Safelight?".

Assessing when the film is done takes practice. Use the recommended development time and see what it looks like under the safelight for a starting point.