[alt-photo] Re: Multi-Neg Printing Methods
workshops at polychrome.nl
Sun Oct 30 11:08:12 GMT 2011
I don't know how Salto actually is doing this, but knowing the company has a printing background it is not difficult to imagine that these negatives are in fact separation negatives. When using software like Icefields (isisimaging.com) it is possible to prepare an image for quadtone printing. Instead of a negative set representing CMYK channels one gets a set of negatives representing 25%, 50%, 75% and 100% K with a nice overlap. Each channel has to be printed in register with the right ink dilution. In fact that is what QaudToneRip is doing too.
How to translate this to platinum I don't know. But it should not be to complicated when you realize that each quadtone channel only represents a specific tonal part of the image and blocks the rest. Like a C channel negative doesn't print YMK information.
Just a thought experiment ;)
On 30 okt. 2011, at 07:32, Francesco Fragomeni <fdfragomeni at gmail.com> wrote:
> What I think I've stumbled upon is that Salto makes his negatives by
> separating channels rather then making negatives actually exposed for
> shadow, midtones, and highlights as I had assumed. It is these separations
> that are made into negatives and then printed which also removes the issue
> of the over printing in the mids and shadows. I don't believe Salto uses
> masks (that was my assumption at first) and the channel separation
> technique answers why he doesn't need to use masks. Also, this brings some
> light to other information that I've come across in the past regarding how
> Penn made many of his negatives. From my understanding part of his
> technique was to use filters to create a similar kind of channel
> separations which also accounts for the fact that he didn't use masks
> either. I think the key is working with the channels in negative form which
> will behave very differently in printing then negatives exposed for the 3
> primary tonal areas.
> Thank you for your help and for thinking through this with me. Hopefully
> this may develop into something that I can use in my printing.
> On Sat, Oct 29, 2011 at 11:04 PM, etienne garbaux <
> photographeur at nerdshack.com> wrote:
>> Francesco wrote:
>> My primary concern is exactly what you
>>> describe in your response on exposure. I understand that the "shadow neg"
>>> will be blocked up in the mids and highlights effectively producing little
>>> exposure in the midtones and highlights in the print. Likewise, the
>>> highlights values will be blocked up in the "midtone neg" preventing most
>>> exposure to the highlight areas of the print. My concern is that the areas
>>> in the "midtone neg" and the "highlight neg" of lesser density will cause
>>> overprinting over what has already been printed in the lower print tones
>>> the previous negative printings. Is this just a non-issue for some reason
>>> that I'm not seeing or is any increase in density in the mid and lower
>>> tones simply something that needs to be worked out and compensated for
>>> through test strips? I'm just not seeing how the mid and low print values
>>> can be maintained after the "midtone neg" and "highlight neg" are printed.
>> I have only very limited personal experience in using multiple negatives
>> this way, and that was long, long ago in a darkroom far, far away. I know
>> others who painted the shadow areas of their mid and highlight negatives
>> with masking shellac to solve this problem, but that was a bit too manual
>> for me. As I said before, I quickly took up using the Dye Transfer process
>> to make Pt negatives, and more recently I have used straight-line films,
>> overexposure, and hearty development to make in-camera negatives with a DR
>> in the 2.5 to 2.7 range and a Dmax near 3.0 (i.e., no image areas less than
>> 0.2 to 0.25 density, so all of the shadow areas are well off the toe). I
>> now actually like Pt prints better this way than with artificially
>> fortified shadow tones. There is enough shadow contrast (way more than
>> most contemporary Pt images I see), but not so much that the prints look
>> "tarted up" with artificial shadow tones.
>> The fact that Salto is reported to use sandwiched "negatives" for the
>> midtone and highlight exposures suggests that one of each pair is actually
>> a positive mask used to control the shadow exposures through these
>> In the bad old days, we used a generally similar method to control
>> contrast, using Kodak Commercial and Professional Copy films (moment of
>> silence for the loss of two of the most useful sensitized materials ever
>> made). There is lots of old literature on "contrast masking" (not to be
>> confused with the relatively recent practice of "unsharp masking"), some of
>> which would likely be relevant to your quest.
>> Now: Since Salto is using imagesetter negatives, I'm not sure I see the
>> need to actually create film negatives and masking positives -- one should
>> be able to design curves in the digital domain for the highlight and
>> midtone negatives that accomplish the masking directly on the negatives.
>> But then, I have no familiarity with his process and all of what I have
>> said about it is purely speculative (though seemingly plausible, IMO).
>> Best regards,
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