Dodging and burning

[rbconbautista]

Just a few quick questions. Does the aperture on the enlarger lens have anything to do with exposure time. For example if you were at f/8 at 10 seconds would f/5.6 at like 5 seconds would give you the same exposure. And should i use a smaller aperture if I'm planning 0n dodging and burning.

 

[IanG]

You've got it, short times make dodging more difficult. I tend to use a second exposure for burning in but it can be done in a single exposure. You'd be better stopping down to f11 and 20 seconds in your example if doing quite a bit of dodging.

Ian

 

[compur]

Just a few quick questions. Does the aperture on the enlarger lens have anything to do with exposure time. For example if you were at f/8 at 10 seconds would f/5.6 at like 5 seconds would give you the same exposure. And should i use a smaller aperture if I'm planning 0n dodging and burning.

Yes. Yes. Yes.

 

[Derrel]

You are absolutely correct in your mathematics. I like a slightly longer exposure time when I need to do dodging or burning. A five second time is basically too short especially for repeatability

 

[webestang64]

FYI- I always use f8 or f11 to print. Sometimes f16 for a lot of dodge/burn.

 

[Derrel]

One way to categorize the amount of dodging or burning needed is as a percentage of the main the exposure. For example let's say the main print needs 10 seconds, but certain light areas need to be burned down 50%. With a 10-second exposure adding 50% is easy and repeatable but if your main exposure is only 5 Seconds you have only 2.5 seconds in which to make the needed burn- in, and that is extremely difficult. It is better to have a main exposure time of around 15 seconds or so, so that you have adequate time to make smooth Dodges and burns. One thing to check though is to make sure your negative does not suddenly pop! and change its focus. How long this takes depends on room temperature and your particular enlarger. If your main exposure is somewhat long, let's say 30 seconds, it is not too uncommon for the focus to suddenly pop! as the film changes its position in the negative carrier. The same thing happens when you project slides: the slide comes on and if the focus is set with the slide cold, after a certain length of time the film will pop! within the transparency mount and will shift focus. If you are going to make a relatively long exposure, such as with a tremendously overexposed, very dense negative ,then I would encourage you to allow the film to buckle or pop! And to set the focus only after the film has popped.

 

[vintagesnaps]

Early on for me learning darkroom work the owner of our local camera store (who retired/closed up shop some years ago) had told me that f8 and 11 seconds or f11 and 8 seconds is a good starting point. And sure enough, I found that worked about as well as anything.

Those settings might need to be adjusted, but I prefer something like f8 and 11 seconds (or settings that have the aperture closed down more to need longer exposure times) to have more time to dodge. But then, I like to play with my dodgette set that I got at a camera swap.

I don't think I've ever had a negative pop. Or snap, crackle! (Had to.)