Ilfochrome/Cibarchome exposure question

[newmoon2night]

I could very well be completely wrong with this, but I vaguely recollect being told quite a while ago, that to get the best results with Ilfochrome/Cibachrome prints, the transparencies should be slightly over-exposed.
By this I mean overexposed when shooting the photograph, not when making the print.
Is there any foundation in this, and if so by how much should one overexpose?
Thanks

[bob carnie]

Hi There
just the opposite: slightly underexpose the transparancy or normal.
a flat scene will reproduce better than a contrasty scene as well

I could very well be completely wrong with this, but I vaguely recollect being told quite a while ago, that to get the best results with Ilfochrome/Cibachrome prints, the transparencies should be slightly over-exposed.
By this I mean overexposed when shooting the photograph, not when making the print.
Is there any foundation in this, and if so by how much should one overexpose?
Thanks

[percepts]

I could very well be completely wrong with this, but I vaguely recollect being told quite a while ago, that to get the best results with Ilfochrome/Cibachrome prints, the transparencies should be slightly over-exposed.
By this I mean overexposed when shooting the photograph, not when making the print.
Is there any foundation in this, and if so by how much should one overexpose?
Thanks

well with transaprency film it is the opposite of negative film. i.e. you expose for the highlights and not the shadows. That means any overexposure and your highlights will be blown out so normal or slight underexposure will give you a useable tranny.

Having said that, transparency only accepts between 5 and 7 stops of subject brightness range. Maybe a little more but it depends on the particular film you are using. Either way there is little if any room for getting exposure wrong so very careful metering is required for optimum results or they will be difficult to print. Too much exposure and shadows block up, too little and highlights are blown. So all depends on which film and the subject brightness range. A bright sunny day with deep shadows will be a problem. This is one reason why people shoot at dawn or dusk. Good side lighting and lower contrast range.

[Bill_1856]

Actually it's true that an overexposed tranny will be easier to print on Ilfochrome because of the reduced contrast. The problem is to make the original without washing out the highlights. They are two seperate problems.
If you're goint to print chromes, you'd better learn how to make contrast and highlight masks.

[Drew Wiley]

You have a couple of major problems with Ciba. The first is the relatively high level of
contrast of the print medium itself. This is an advantage if you know how to handle it.
Taking a shortcut with the film itself is basically the wrong approach. You some of the
older tranny films you could "pull" the E-6 dev a half stop of so to obtain less contrast
in the highlights. Or nowadays, you could try a film with less overall contrast like Astia.
Underexposing or overexposing is merely going to destroy information at one end of the
scale or the other. The second problem involves the inherent gamut reproduction errors
inherent to the dyes. No kind of direct fiddling with film or developers will correct these. The only reliable answer is to learn unsharp masking, which is capable of
simultaneously balancing the medium for both contrast range and hue shifts. Simple
in principle, but like many other darkroom skills, with a distinct learning curve which
requires a lot of trial and error. People make a lot of fuss about that kind of thing
nowaday, but at the time Ciba was introduced it was marketed as being extremely
simple! And I don't think it's any harder than sitting on your ass for hours and hours
making correction in Photoshop. But make sure you have good ventilation! The bleach
is nasty.

[joeyrsmith]

I second that with Drew.
When I printed Cibas back in the early to mid 90's.
I made contrast reducing masks, which worked miracles.
Actually, almost 80% of the commerical prints I made had to have a mask.

[newmoon2night]

Thank you for all the responses.
Thanks in particular to Drew for a very comprehensive response.
From the responses I am concluding that the best option is to expose the transparency as 'normal' - for correct exposure and maximum dynamic range, and not get into over or under exposing for Ciba printing.
At this stage I don't do my own printing, but send out to a lab that has done Ciba printing for ages (I'm in the UK and the lab is the excellent BPD Photech (http://www.bpdphotech.com/);I have used them many times in the past.
I don't have the space at home to set up a darkroom that I could ventilate anything like sufficiently for this.

[GPS]

...

Having said that, transparency only accepts between 5 and 7 stops of subject brightness range. Maybe a little more but it depends on the particular film you are using.
...

That is a wild dream about slide films. The OP should check this assumption with official data on chrome films to get back to the reality. :(

[Ivan J. Eberle]

Densities for a good punchy transparency to project or drum scan, and an optimal transparency to print on Ilfochrome will be markedly different. Under exposing over over exposing isn't the answer, but rather modifying the light or waiting for lower contrast when shooting available light. Ideally you're shooting for a transparency with a modest 4 stop or less brightness range, with "exposure to the right". Don't block up the shadows, and get the important detail well up on the toe of the film.

Such a transparency will be vastly easier to print on Ilfochrome. Keep the density within bounds and you won't need to source unobtainable contrast masking materials like Pan Masking Film nor find viable substitutes, nor worry about finding or fabricating a registration punch, mask contacter and enlarger stag--let alone whole learning curve and technique just to get a decent print.

You'll soon learn to look at a slightly washed out looking slide with the smug confidence that the slightly less saturated color will enjoy a healthy contrast and saturation boost in printing.

Even though someone is bound to chime in with how they're substituting other film emulsions to make unsharp silver masks, avoid if you can that rabbit hole if you want to enjoy Ilfochrome. Print the easy stuff first, and leave traditional silver halide contrast masks out of the learning curve for now. Besides, it's VASTLY easier to scan a dense chrome and do a digital interneg these days, with much more fine-tunable results.

[Drew Wiley]

Well I will chime in, Ivan. The point of masking for Ciba, as I pointed out already,
is gamut correction as well as contrast. Simply having a sufficiently low-contrast
transparency rarely cuts it. Masking also helps distribute contrast. In other words,
if it can be scanned and printed, it can also be printed on Ciba. Obviously, the complexity of such a task varies with the specific image, just like it would in digital
output. But if the information is on the film, there's generally a way to print it on Ciba with excellent results, provided this is the kind of look you're after in the first place. Forget the good old days with Pan Masking film. There are in fact better
substitutes today if you also know the correct developers for this kind of work.
Sometimes this turns out to be complicated, with multiple masks involved; but more
often a single mask is adequate. I don't know how anyone can suggest the overall
workflow is harder or easier than Photoshop manipulations. It all depends on your
experience and inclination, that is, whether you like or dislike darkroom work.
I like it.

[sgelb]

That is a wild dream about slide films. The OP should check this assumption with official data on chrome films to get back to the reality. :(

agreed.. its more like 3 IMO. even at 3 over, you will lose all highlight definition.

[Drew Wiley]

Like any print medium, one has to learn how the paper sees the image and not just
how it looks on a lightbox. When I'm shooting for Ciba I avoid Velvia except for low
contrast scenes in the fog or mist, when a contrast boost is actually helpful. If you
gain experience with highlight masking as well as contrast masking you can gain
control over full contrast scenes. But it's obviously important to first experiment
printing without any masks simply so you begin to understand what kind of mask is
needed. Then you can register masks visually on a lightbox for simple experiements. But anything serious requires a registration punch and frame or you
will go insane.