New enlarger, print time

[mrtoml]

I just got hold of a used LPL C7700 and have been printing a few black and white 10x8s. It's been a long time.

One issue I have is that print times seem overly lengthy. Say, with filtration for multigrade, 40 seconds at f8. Is this long? I read often that people seem to get to around 10 seconds, but I can get nowhere near that.

Do the bulbs fade in these things or could it be something else? Or is this actually OK?

 

[Finder]

You can change your bulb. Do you change the condensor position with format? How are you neg densities? 40 sec is only two stop longer than 10 sec so a few things can make a difference.

 

[Solinar]

Is that a color enlarger with dichroic filtering? You may not be able to change the wattage of the bulb.

 

[mrtoml]

The time I am using is to get maximum black using a blank 35mm, but developed negative onto a 10x8 sized paper.

It is a colour enlarger so I dial in magenta for increased contrast. With no magenta at all I get a time of around 30 seconds (i.e. for grade 2). As I dial in magenta the times get longer as expected.

 

[Finder]

Sorry, I did not realize it was a color head - no condensors. Are you printing color negs or B&W negs? B&W neg densities are much higher than color. The diffusion chamber make color enlarger illumination weaker than condensor enlargers. Some color enlargers have different diffusion chambers for different formats because of the loss of light when going to smaller negs - the magnification increase and hence exposure.

 

[mrtoml]

Hi

I'm printing black and white negatives, but they are pyro stained which I understand makes a difference.

Mark

 

[Finder]

Hi

I'm printing black and white negatives, but they are pyro stained which I understand makes a difference.

Mark

There might not be a problem with a 40 sec exposure time. A color head with dense silver negs would not make that exposure time strange or unusual. The only practical problem would be that reciprocity may be compounding the problem especially if you start going with longer exposures for a burn.

 

[mrtoml]

Just for information. I replaced the bulb and now everything is OK. The halogen bulbs in these dichroic heads obviously fade significantly with age. I replaced it with an identical spec and now my times are down to ~10 seconds whereas they had been ~30+ before.

I also ordered a darkroom f stop timer/analyser which actually deals with reciprocity failure (not that this would probably be an issue now).

Regards,

 

[Solinar]

Mark, thanks for the update. 10 -15 seconds is much at f/5.6 to f/8 is the range I usually I get.

 

[fidget]

I recently obtained a Magnifax 4a with color 3 head. This has a neutral density control which has proved unexpectedly valuable in lengthening exposure times TO around 40 seconds whilst keeping a nice aperture of 8. This gives me the time for dodging and burning which is more difficult at shorter times.
I guess that most of your work is "straight" exposures, so a wait of 40 secs may feel too long?
I remember my first enlarger, an Opemus 5 with B&W head. It gave exposure times of around 3 seconds at f11. It was still short with a lower wattage bulb fitted.

I'm not sure at what point paper exhibits reciprocity failure. I used paper in pinhole cams and believe that I haven't seen this in exposures lasting nearly an hour.