Dev Time: Condenser -V- Diffusion

[Bruce Osgood]

Before I do anything regarding a test, I would like to ask if anyone knows what outcome I might expect.

My concern is with the sharpness of the print. I am not convinced I am getting all I can in terms of print sharpness and have tried about every film manufactured; I have tried a multitude of developers with little or no satisfaction in what I perceive as sharpness in the print. I have aligned and realigned my enlargers to no avail. My lenses are first class and I use a tripod.

For 4X5 negatives, I use a Jobo CPE2 with lift for developing and as every manufacturer of film and chemistry suggests I use a reduced development time to compensate for continuous rotation.

My 4x5 enlarger is a D-5 XL with Super Chromega D head.

I am considering the possibility that the reduced time (15%) may not be a good idea when printing with diffused light.

My questions become: Does diffused light produce a "less" sharp image from an otherwise sharp negative and would increased development compensate for it?

Thanks,

 

[Jon Shiu]

Hi, if you really need the extra sharpness, I would switch to a condenser enlarger. In my own experience, for most images it doesn't make that much difference, but I have one image of sand that I could never print satisfactorily on diffusion and had to switch to condenser.

Jon

 

[RalphLambrecht]

... Does diffused light produce a "less" sharp image from an otherwise sharp negative and would increased development compensate for it?

Yes and no, respectively but neither is your issue, I think.

Let's start by defining sharpness (see attached). What we perceive as 'sharpness' is a combination of acutance, contrast and resolution. Optimize all three and you'll have the 'sharpest' image possible.

Resolution
good optics, optimum aperture, tripod, low grain film, negative format, negative magnification, enlarger alignment, print viewing distance

Contrast
subject and subject lighting, proper film and paper exposure, appropriate negative contrast, matching paper contrast, no safelight fogging, no stray light (camera and darkroom)

I hope you've done all of that. One variable is left:

Acutance
developer, agitation

Before you do anything, make sure your contrast is where it needs to be. Contrast is the main influence on sharpness. However, from what you told us, acutance might need improvement too. Are you using an acutance developer? (unfortunately limited with LF). Have you tried stand-development? Rotation development suppresses acutance (I use it anyway). If that's not enough, increase acutance with unsharp masking (that's how Photoshop increases sharpness).

 

[Bruce Osgood]

Wow, I really didn't expect this level of response, thank you very much.

My questions become clearer to me by realizing my concern is actually about acutance and contrast and not sharpness. This is something I can tinker with without reinventing the wheel.

Maybe I need two copies of Way Beyond Monochrome.

 

[RalphLambrecht]

... Maybe I need two copies of Way Beyond Monochrome.

One copy should be enough!