Safelights + Printing
A basic question but I have not found a clear answer anywhere.
I routinely turn off the safelight when I expose variable contrast FB printing paper. I have seen others print with continuous use of the safelight. I have done appropriate safelight tests with no problems/fogging.
Should I continue to turn off the safelight or should I not worry about it and just leave it on? Thanks.
If you have done a safelight test and by that I mean exposing paper to just below exposure threshold and then doing the test, then you should be safe in leaving it on. To do the test without a threshold exposure is meaningless.
VC paper is more sensitive to fogging then graded paper.
I've never fogged VC paper (or any other for that matter) by exposing it under a safelight. I suppose that with extended exposure it could fog, but with normal processing, no worries.
Searching my way to perplexion
Originally Posted by t_nunn
This depends on the colour of the safelight for some papers need red and others need amber, such as the Ilford 902. My preference is to switch off the safelight when I expose the paper and, if necessary to switch it off if I choose to extend the paper development.
Don Miller has metioned the need to carry out the proper safelight test where the paper is presensitised, I cannot stress enough that this is an essential requirement. I test my safelights once every year, for filters do change over time and you could be experiencing slight safelight fogging without realising that it is happening.
In the remote past I think it was relatively common to turn off the safelight during the printing exposure. Some enlarger timers even had a safelight circuit that automated that action.
I generally do not turn off the safelight, but there are two possible exceptions to that rule. One is if the enlarging exposure is unusually long. It may not be necessary, but it seems like a prudent caution to avoid any possible fogging. (Yes, I have tested my safelights so I know they won't fog - but I'm a belt and suspenders type of guy.)
The other situation is if the negative requires a lot of intricate burning and dodging, I amy turn off the safelight to be better see the image on the paper.
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My safelights are on dimmers. For long exposures they can be turned down or off. Don Miller is right about pre-exposing paper for a safelight test. The most informative test is a step wedge exposure to white light followed by a step wedge safelight exposure at right angles to the first. This shows the white light exposures that are most affected by the safelight. The results suprised me.
Unless you are doing a lot of print manipulation the print exposure is usually short compared to the overall exposure to the safelight during processing.
There is a strange phenomena which can happen with variable contrast papers used with the wrong safelight, usually red/orange.
This causes a lack of contrast at the higher filtration settings. Les will know about this, as it prompted Ilford to introduce the Amber safelight filters, and other manufacturers follow their lead.
When I had a large commercial darkroom like Jim I had the safelights on dimmers, and for long exposures or exposures using multiple enlargers would drop the level, quite significantly.
And just to hark back to Les McLean and fading filters, safelight fogging is not always visible in simple tests. I suppose a good analogy is an unsafe safelight which doesn't appear to fog paper is actually extrordinallyy similar to post or pre flashing a print to reduce contrast.
You young pups fergot how it used to be back in the day...
Most timers cut out the safelight anytime the enlarger bulb was on, for either exposure or focus. On the focus end, before these really fancy scopes when one had an old B&L or just looked real close at the paper on the easel, it was much easier to focus.
On the exposure side, its much easier to dodge and burn at smaller aperatures when you can see without the washout of the safelight.
Like anything else, habits carry on even after a specific need passes. In reality it doesnt make any difference whether it is on or off, as long as you can get done what you are trying to do...
When you come to a fork in the road, take it...
I keep my amber LED safelight on. I use mainly FB VC paper and I have tested it for 15 mins so I know there is no worry about long dodge/burn times. Having said that, as pointed out above, I do have to turn it down sometimes so I can see what I am doing dodge/burn wise because it can be too bright.
Bottom line as others have said is to test it for the maximum time you are likely to have the paper out using the pre-fogged paper method.