Camera lens on enlarger for making enlarged negatives

[jim_stewart]

I have been making Kallitypes using 4x5 negatives and want to start

making bigger prints. My first thought is to make a TMX interpositive

and then to enlarge the interpositive to make the final TMX negative.

Because of the speed of TMX I am expecting fairly short exposure

times. Rather than trying to use mylar drafting film above the

negative to act as a neutral density filter I am wondering if it

would be possible to use my 150mm camera lens on the enlarger and

control the length of the exposure with the shutter. If it is

feasible would using a lens such as the G-Claron give better results

than my Xenar?

 

My second thought is to use a color transparency as the original

image and projection print it onto TMX of the desired size in order

to get a second generation negative rather than a 3rd generation

negative as above with the interpositive. Would the shorter exposure

scale of transparency film present any problems?

 

Thanks in advance for your thoughts on these ideas.

[jimvanson]

With a enlarger lens your looking at a design featuring flat field and even coverage. I wonder if your camera lens is able to reproduce that?

[donald_miller1]

Your Xenar is not optimized for flat field work in the same way that an enlarging lens is. I think that I realize your motivation, but I would do some more discerning of choice of materials in making enlarged negatives. Bob Herbst has written a good article on enlarging negatives on Ed Buffaloe's site www.unblinkingeye.com. Bob uses Tmax 100 as a contact printed interpositive and ortho lith film for the enlarged negative (ISO of that material 4) Additionally John Rudiak and others have articles posted on enlarging negatives (these can be located by doing a search under platinum printing).

 

My thoughts on using a color transparency is... Why??, other then eliminating an interpositive. The downside to that consideration is that you are dealing with a positive which has limited exposure latitude (7 stops versus 12 stops on black and white film) even when it is properly exposed and processed. Good luck.

[michael_kravit]

First,

 

TMX makes great interpositives or diapositives. TMX is a fairly fast film so you

will most probably want to place some neutral density in the light path. Using

your LF G-Claron would work fine as it is a process type lens. Mounting it and

getting an acceptable enlarger height with 4x5 might be another issue.

 

I would stay away from color tanny film. It will work, but your enlarged negs

will be overly contrasty and will most probably loose valuable shadow detail.

 

Making enlarged negatives is very easy once the process is learned and you

nail the expsoure times and processing times to obtain the density range you

are looking for,

 

Buy some neutral density gels and you are on your way.

 

Mike