F Stop Help

[PlantedTao]

I need help on F stops and what they mean on the enlarger when making a B&W print.
I understand what they are in the sense of my camera. Does the same apply on the enlarger? The larger you open the aperture the more light and the less DOF...is that true when making a print? Every book I read about printing seems to use the sweet spot on the lens F8 - 5.6 and then just adjust the time. They don't explain why you would choose different ones. Why have different ones?
I'm confused.
Also, anyone have any good suggestions on books that could help me in the darkroom for B&W Printing?

Thanks.

[another view]

This is a pretty good book, it's a step-by-step guide for developing negs and making prints.

Most lenses, whether for cameras or enlargers, are supposed to be sharpest in about that range. With cameras, you know why you'd use that range or something outside of it. Having never made a darkroom print I really can't answer why you'd want to use a wider or narrower aperture on an enlarger, but I'd think you'd want the print as sharp as possible - to get every bit of detail out of it that you can.

[Chunk]

There were times when I wanted a bit more time for controlling dodging or burning and used a smaller aperture for longer exposure times. The difference between 10 and 15 seconds is more easily repeatable than the difference betwen 1 and 1.5 seconds. I haven't done anything in the darkroom for years so I am sure there are better answers.

[mjs1973]

I think Chunk and Steve pretty much summed it up. The extra time you can gain for burning and dodging is a big reason for exending the exposure time under the enlarger, and you want to get your print as sharp as possible, unles for whatever reason you artistic view tells you differant. As far as the DOF goes, that was already captured in camera, on your negative. Your print is just a reveresed version of your negative.


I have this book and it looks like there is a lot of good, how to and step by step info in it, but judging by the fact that my bookmark is only on page 9 after getting this book a year ago, I really can't say if it's a good book or not.

If you just think of the f/ stop as a unit of measure in the darkroom, it might make things less confusing.

[PlantedTao]

OK - Thanks guys.
That makes perfect sense about clarity and that was kinda my line of thinking...except I used the wrong term - DOF.

The time issue is very interesting and after trying my hand (pun intended) at burning and dodging I can see where this could play a vital roll.

I'll check out those books - or atleast the one AV suggested - I really don't need 20' of headphone jack mjs??? But if I do I'll head down to radio shack ;)

Cheers.

[mjs1973]

Hahaha, I guess I should have checked my link! I fixed it now. I have another photo book by the same author and it's pretty good, so I'm sure the darkroom book is good too. Just haven't gotten around to reading it.

Be carefull in your class, the smell of photo chemistry is addicting! I just love the smell of a photo lab.

[Lionheart]

I need help on F stops and what they mean on the enlarger when making a B&W print.
I understand what they are in the sense of my camera. Does the same apply on the enlarger? The larger you open the aperture the more light and the less DOF...is that true when making a print? Every book I read about printing seems to use the sweet spot on the lens F8 - 5.6 and then just adjust the time. They don't explain why you would choose different ones. Why have different ones?
I'm confused.
Also, anyone have any good suggestions on books that could help me in the darkroom for B&W Printing?

Thanks.

Wow. Been a long time since I've done real darkroom instead of pc-darkroom. Mostly I used the enlarger stopped down to control the exposure better. Longer exposures are easier to work with (more predictable) when you have primitive analog timers like I had in the old days-analog as in I hit the switch off and on when the beeper went off I don't know if the edges were sharper or not when stopped down, really couldn't tell the difference-my equipment was a 50 yr old Besseler b&w enlarger with hand filters for printing from color slides. I never did much color negative, and no b&w-just couldn't get into it back then.

[mdcalaska]

DoF is a non-factor in Enlarger lenses/F-stops: A Flat negative printing to a Flat peice of paper . . . (making both perfectly flat is another topic ) )

Enlarger F-stops mostly used in the "Sweet Range" for some small control on time. Enlarger lenses are of the "Flat-Field" style and perform poorly outside the sweet range.

Longer exposure times on paper can "Muddy" whites and light greys - also can burn some edges in while softening others.

Score a set of ND ( Neutral Density) filters and you can experiement with changing a 4 sec exposure to a 35 and see the effect. Part of the FUN of doing B&W printing.

Or do half the exposure time - pull the neg carrier - "flash the paper with the enlarger light - then replace the carrier and finish the exposure time. Solarization. If you get a killer looking print from that you'll spend the next 8 weeks trying to repeat the same (seems like no 2 alike!)

FYI- Kodak stopped production on all their B&W papers last month - the distribution chain will empty by early 2006. I think the Kodak B&W chemicals will stay around - Medical x-rays are a big chunk of Kodak's business. Ilford makes a solid line of B&W papers.

Like mjs says - the smell of Fixer in the morning . . . smells like Victory

[Chunk]

DoF is a non-factor in Enlarger lenses/F-stops: A Flat negative printing to a Flat peice of paper . . . (making both perfectly flat is another topic ) )

If you tilt the the paper for any reason (like the poor man's perspective control) you may want maximun dof.