Chrome pos ---> B&W Neg

[Jeff Searust]

Ok I need some advice. I have a chrome (slide) 6x7 positive, and I need a B&W negative so I can print with it.

My idea is to put the positive in the enlarger and focus it to 4x5 size then put a 4x5 B&W negative on the base. My enlarger control will do .1 second of exposure, and I can disable the safelights from coming on and immediately develop the negative.

I only have 100 speed 4x5 film so I am wondering if it is going to be a futile effort or is this a reasonable thing to try.

Anyone have any other ideas?

 

[Nicholas Lindan]

Reasonable thing to try.

 

[pentaxuser]

From books and prints in such books that I have seen - I have never tried it myself - you can make a reasonable B&W print from a slide by contacting the reversal print to another piece of B&W paper.

Might be simpler unless you intend to do a lot of prints from the slide.

pentaxuser

 

[glbeas]

The film will probably need to be developed to a higher contrast than you would use for pictoral photography to get a really good negative from it.

 

[Mike Crawford]

This is a good practical way to make internegs. We used to do loads of these in a lab I used to work at. Main thing is to cut the dev to reduce contrast, then base the exposure round that. As I remember, Plus X was developed at 4 mins in ID11 instead of 6-7 minutes. (Don't quote me; it was about 15 years ago) At least reduce the dev by a third, maybe even a half. (Tmax 100 was not good for this though.) Exposures were brief, but fine to do if your timer has tenth of a second. 1s at f16 rings a bell though maybe that was duping. Best to test a bit. Depends on the light source though obviously no filters should be used. Tranny should be upside down in the carrier so it reads the right way on the negative. For convenience, film was loaded into darkslides and we had one darkslide with white paper to focus on which was placed on an adapted baseboard. Cutting the dev too much will make it mushy though and you may want to use diluted dev to ensure longer and more accurate processing times. Good luck!

 

[Jeff Searust]

I was going to do it in a 4x5 film holder, just waste one side's film focusing with the grain focuser, then cut lights, flip it over and do the exposure with the other side. I am going to give this a shot in a couple hours and will post results.

 

[nickandre]

Paper is not sensitive to any reds and will show most blues as complete black. It's a rather unnatural effect. Unless you have a stash of panalure I would make an interneg.

 

[keithwms]

I generate b&w negs from slides quite often, I like the look. I typically enlarge 35mm or medium format chromes to 5x7 tmax.

What you can do, to try to get the contrast right, is do test strips. So you expose the neg in sections, just like you would to do an exposure check for paper. then if you really want to get fancy you can cut the neg perpendicular to that and develop N-1, N, N+1 or such, and just see what you like. But honestly I normally just wing it and by the 2nd or 3rd try get roughly what I want. To really make it work, though, you need to mind your exposure- any highlight detail close to lost on the slide will be really hard to reclaim in the neg.

Of course, your b&w film needs to be panchromatic or the tonality will be rot.

 

[Jeff Searust]

I am going to take a couple of the variables out- I am going to expose tmax 100 and develop in Diafine. I will expose for .1 second with the enlarger head set on the regular height for contact sheets. The only variable I want to adjust will be the f-stop on the lens. I will start at 16 and see what that looks like.

 

[Michel Hardy-Vallée]

I've been meaning to do this as well, so let me ask a related question: would there be a big difference in quality between enlarging to a negative and then contact print vs. contact printing a negative on film, then enlarging the resulting neg? Any advantages/disadvantage?

The only one I can see for sure is the cost of film. Suppose I start from a 35mm slide: 8x10 TMAX would cost me a lot more than 35mm!

I've got a Leitz ELDIA, so contact printing 35mm on 35mm is pretty easy.

 

[richard ide]

If you find the contrast is too high and you lose detail in shadows, you can make a contact on your BW film and generate a low contrast, low density positive and enlarge both in register on to your film. If you have a neutral density filter, you can get more control on your exposure. Using a very short exposure, your lamp may not heat up enough to give you a good lamp colour output. From experience, exposures are more reliable for this if you can extend them to 5 seconds or more.

 

[keithwms]

I've been meaning to do this as well, so let me ask a related question: would there be a big difference in quality between enlarging to a negative and then contact print vs. contact printing a negative on film, then enlarging the resulting neg? Any advantages/disadvantage?

When you enlarge to a neg, you are also enlarging the grain in the parent slide, which is typically minor. From slide shows in our youth, we all recall how nicely slides enlarge!

But you dupe by contacting first and then you enlarge, you are of course enlarging the grain of the b&w film in proportion to the image itself. That grain might be more prominent than that of a chrome of the same size. (Then again you might like the effect...)

A few other things.... retouching a larger neg is easier, but on the other hand, as you mention, the cost of the large film can be a bit high, especially since you can't usually use ortho or similar non-pan film.

The larger neg gives you some alt printing options, and also makes final printing easier: I like the idea that my enlarged negs can be contact printed with ease at some later date, without even needing an enlarger.

In either workflow you are of course going to lose some information through enlargement.

As usual, the best option is to try a few things and see what works for you!

 

[Jeff Searust]

Ok---results and what I did;

I took a 4x5 film holder and removed one darkslide ---wasting one sheet of film to use as a focus platform, then set the enlarger to .1 second, flipped the film holder, exposed the other sheet of film just about 1 to 1--- maybe a bit larger. Than I developed the film, stopped, and fixed it.

A-- it seems that slide film...and this was a 6x7 chrome, has a larger focus latitude than B&W film. What I mean is that using a grain focuser, I was not really able to get a perfect focus. It looked good in the grain focuser, but....

B-- The density was great, and it looked for a while that I had pulled it off, but upon removing the film from the fix, it looked blurry -- unfocused a bit. I think this is the major stopping point.

C-- I will attempt again, but I want to put the chrome face to face with a sheet of tmax under my contact sheet glass and see if a contact "print" is the way to go.

 

[2F/2F]

It will work. You will need to do some test runs, of course. One change I would make to your plan would be that I would simply contact the film instead of enlarging. You can rig it with something as cheesy as a cheap thrift store picture frame if you want. I have done this very successfully with graphic arts film in $1.00 5x7 and 11x14 frames, and even pulled off a successful 4x5 contrast mask one time. You just might have to throw some card stock shims in to hold the two emulsions flat against each other. If you are getting Newton's rings after a few tries, you can invest in a piece of anti Newton's ring glass. Assuming an average tungsten enlarging lamp, I would also put 80A and 82A gels stacked in the filter drawer, so you don't get an orange-filtered effect on the b/w neg. You can even do this onto little strips of 120 film instead of a 4x5 sheet. I would personally prefer the 4x5 sheet, however, to give me an edge to handle and a more sturdy base material. I'd also raise your enlarger all the way up to give you finer control, and you may even want to use ND filters.

I also assume you realize that you'll be printing through the base material when you go to make your silver print from the neg. you just made...that is if you don't want the original orientation to be flipped for the print.

Also, reciprocity failure, of course...therefore T-Max (or Neopan) *is* a very good choice.

 

[Jeff Searust]

I think the ND filter idea has some serious merit here. I really have no issue if the neg is flipped however.

 

[trexx]

You should stop down more, get longer exposure times in the .4 to 1 sec. range. Also try to get a bigger enlargement
To focus find a point on the neg. that has a big difference in contrast. You may not find grain but a sharp edge can serve as a point of focus.

TR

 

[Jeff Searust]

we've been hashing this around at the office today, and no one is coming up with a reason not to do this as a contact neg-- just putting the 4x5 film and 120 positive together with a glass over them and flash that with white light.

 

[2F/2F]

we've been hashing this around at the office today, and no one is coming up with a reason not to do this as a contact neg-- just putting the 4x5 film and 120 positive together with a glass over them and flash that with white light.

This is a much better option, IMO (as I said above, though I did not say why I thought so), for more than one reason.

First, you get the minimum possible generation loss (aside from scanning). No enlargement, no lens introduced into the equation, etc.

Next, you don't have to focus such a tiny image. Less chance of user-introduced (focus) and equipment trouble (misaligned enlarger, shaking enlarger) into the process.

Third, you can raise your enlarger higher to get finer control.

Additionally, you want an exposure long enough to give you the fineness of control that you need to get the ideal exposure (1/3 stops are fine). I would not fear reciprocity failure too much. For one thing, you can get a film that has great reciprocity maintenance during long exposures. Even with reciprocity loss, you sill want longer exposures, however, IMO. The exposures I was getting for my masks on Tri-X (EI 320) using my Omega B22XL (all the way up at f/16, and no filtration because I was doing black and white to black and white) were in the range of normal print times. 16 seconds, I believe...and this film loses reciprocity like a muttha$*@$.

Also, remember that you enlarger does not cast white light (if it is using a tungsten bulb). It casts reddish-orange light. You need to add cool filtration (approx. 80A + 82A) to get the light to be white.

Another thing you can do, if you feel so inclined, is to use a flash to make the exposure. I did this one time with litho film using a 500Ws Dynalite studio flash, a small softbox and ND gels because my enlarging lens was loaned. If you have one that can be manually set in third stops, that is great. ND gels may help too. You can use the guide number of the flash or a flash meter to figure a first-try at an exposure. Put the sandwich in the bottom of a black box to prevent the scattered light from hitting.

Any light will work, as long as you can somehow rig it to provide 1/3-stop precision.

 

[keithwms]

Anyway you do slice it, you are going to have to enlarge (either for the neg or for the print) and you are going to have to focus through a lens (again, either for the neg or for the print).

Sandwiching the chrome and the dupe film can (and often will) give fringes. Those fringes will be enlarged... along with the grain of the b&w film, when you make your print.

 

[MartinP]

I have done this professionally, long ago admittedly, and all slide inter-negging was done on 5x4 Plus-x, or the appropriate colour interneg film. The exposure/dev-time was something long forgotten, but I am fairly sure it was several seconds exposure and a shortened development (for the Plus-X, not the C41). Also, I don't recall having to vary the exposure very much between transparencies - but they would have been the very best work and most consistent exposure I suppose.

There seemed to be no problem whatsoever with focussing the slide on a scrap sheet of film using a Peak magnifier, so far as I recall. Black-and-white interneg development was in replenished D76, in deep tanks, same as everything else.

Basically, I'd say you are on the right track with projection printing the tranny on 5x4 in a film holder.

 

[Nicholas Lindan]

The focus problem is more than likely due to using a grain focuser - a slide doesn't have grain, only dye clouds, so there is nothing sharp to focus on. You will get good results focusing by eye on the image detail.

The best results will be from enlarging the slide on to an inter-negative that is the size of the final print, and then contact printing to make the final print. In any case, the internegative should be as large as possible. Making a contact internegative from the slide will result in the poorest results: the internegative will always have less detail than the original and in enlarging the internegative you have also enlarged this loss of detail; dust will also be an enormous problem.

Freestyle sells B&W films for making interpositives and internegatives, but they are blue sensitive, and may not work well with slides - white skies, dark flesh tones, anything red will come out black.

With panchromatic internegative film you can apply filters when making the internegative, such as an orange filter to bring out clouds.

 

[brianmquinn]

Do you have the ability to scan you slides?
If so you could have digital negatives made and print them yourself in your wet darkroom.
The digital negatives can ordered from a lab that will print them on a film of your choice.
OR
You can make fill size ones with an inkjet printer on transparancy media.

 

[analogsnob]

We made B&W internegs for years. Exposure was about 2 seconds f16 or so on Superxx. Whatever film you use today definately reduce development to control contrast. Make the image as large as possible on the neg. Color heads are best for dust but condensers make the sharpest negs. Another way to reduce contrast is to make a second exposure without the chrome in place through a piece of white plexiglass and a 3.00 nd filter. The second exposure can be the same as the chrome or more exposure will give greater reduction in contrast (by supporting the shadow detail).

When focusing check the adjustment of your focuser carefully not all grain focusers are up to the interneg challenge.

If you want to make a neg by contact the sharpest result will be obtained by using a bare filament lamp (one without the white coating available at most hardware stores also called an appliance bulb) placed at least five feet from the contact frame the frarther the better within reason. Be prepared to see all the dust you thought you cleaned off.