Printing a high contrast negative from a negative

[reciprocity]

Im planing on making a high contrast negative from a thin negative via an inter-positive negative and was wondering if someone has experience with this and could advise me.

The negative I'm working from is 120mm and I plan to enlarge it onto a sheet of 4x5 film and then again to create a high con negative.
I was wondering what the best way to make the negative high contrast is? Is it worth me pushing the film a couple stops or would using a magenta filter lead to increased contrast?
Regarding exposure times I was planing on metering it with a light meter (wide open) adding about a stop of light and making a test negative with varying amounts of light around that ballpark figure .

Thanks

 

[Ian Grant]

You might look at the Unblinkingeye website there's an article on making higher contrast inter-negatives by reversal processing.

Ian

 

[Lachlan Young]

Im planing on making a high contrast negative from a thin negative via an inter-positive negative and was wondering if someone has experience with this and could advise me.

The negative I'm working from is 120mm and I plan to enlarge it onto a sheet of 4x5 film and then again to create a high con negative.
I was wondering what the best way to make the negative high contrast is? Is it worth me pushing the film a couple stops or would using a magenta filter lead to increased contrast?
Regarding exposure times I was planing on metering it with a light meter (wide open) adding about a stop of light and making a test negative with varying amounts of light around that ballpark figure .

Thanks

You can either make contact interpositives & enlarged final negatives or enlarged interpositives & contact print the final negs - or you can make enlarged interpositives & 1:1 enlargements for the final negs - a lot depends on the optics available to you & the cleanliness of the glass surfaces of contact printer glass etc. Use Ilford Ortho+ as it lets you use some safelighting (deep red preferably) to see what you're doing. Ideally you would know the density range of your initial negative & the density range your intended print medium requires - then it's fairly simple to judge exposures & aim contrast indices to develop to. Doing it in one step is possible, but potentially a little riskier - here are Moersch's instructions for using lith film. What process are you wanting to aim negs for?

 

[koraks]

would using a magenta filter lead to increased contrast?

No; film is not VC paper.
In principle your process of original negative -> interpositive -> negative will work just fine. At which stage(s) you decide to increase contrast is entirely up to you. Keep in mind that a negative is fairly low contrast to begin with (even a normal one), so you'll have to give the interpositive and/or final negative a decent amount of development. How much development and exposure exactly is up to you to figure out. Be prepared to do a series of test sheets/strips to nail it down. It can be a time-consuming process.
It can be helpful to have a densitometer at hand to achieve better consistency and predictability.

The single step process that Ian and Lachlan suggest is also a possibility but you'll have to do a reversal processing with a permanganate or dichromate bleach. Other than the different development process, the process of nailing down exposure & contrast is essentially the same as for an interpositive process.

Any kind of film can be used in principle for the interpositive & final negative. I've done it with xray film, which is cheap and (sort of) orthochromatic. Films like Ortho + or lith film can also work.

So many many options, but they all come down to doing a series of tests to get the right combination of development and exposure. Go ahead and give it a try; it's not rocket science, just a bit of work.

PS:

Regarding exposure times I was planing on metering it with a light meter (wide open) adding about a stop of light and making a test negative with varying amounts of light around that ballpark figure .

That's not going to work. A ligt meter is intended to give you exposure information assuming the light you measure will then travel through a lens and aperture before hitting the film. Ont he base board of an enlarger the light that's there will hit the film directly. If you measure that light with your regular light meter and work out an exposure based on that reading, you'll overexpose the film by many many stops. Also the (lack of) sensitivity of your light meter will be an issue. Forget about it; just do test strips/sheets. Keep in mind that if you use a film of let's say ISO 50, it's going to be something like 3-4 stops faster than B&W paper. So you'll find yourself working at a small aperture on your enlarger lens, very short exposures or using an ND filter.

 

[Raghu Kuvempunagar]

@reciprocity: This video by @Greg Davis could be of help to you.

 

[ic-racer]

I'd use lithography ortho film for both 4x5 images. The first will be a projection print and the second a contact print. What are you going to do with the new high-contrast 4x5 negative that you couldn't do by just enlarging the original negative?

 

[Peter Schrager]

Use the new bergger print film and develop in pyro ...easy to do and will give you plenty of contrast plus you can work with regular safelight.

 

[DREW WILEY]

I like the double-negative technique. First, a moderate contrast interpositive onto a sheet film like TMax100 or FP4, then the higher contrast final negative with these same kinds of films developed longer for greater contrast. The devil is in the details when it comes to enlarging a small neg to only a modest degree onto 4x5, and then preferably contact printing that onto the final. You ideally need a very clean absolutely flat neg in a glass carrier, along with a lens suitable for small scale enlargements. It also helps if you sheet film holder is vacuum style. Of course, you can experiment to determine proper exposure and development without these amenities, but they definitely do help the final result. I'd avoid anything like ortho litho film unless you simply can't achieve your intended contrast by any other means. It's a headache to control. I realize that a lot of people on a forum like this will argue with this advice and tell stories about how they develop Ortho Litho in dishwater all the time, and it gives them the "artsy" look they are after. I can't dispute that kind of argument, but not everybody likes a print that resembles a moth smashed on a windshield at night with the wipers running. Lith film might be cheap, but you can also waste a lot trying to tame it. Been there, done that.