[alt-photo] Re: Your Approach to Making Negs for Platinum Printing? Ideal Negative Contrast and Dmax?

[Mark Nelson]

Check out DIck Arentz's book PLATINUM & PALLADIUM PRINTING, you can get it as an eBook now and he really covers what you are looking for well.


Best Wishes,
Mark Nelson

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On Oct 8, 2011, at 5:12 PM, Francesco Fragomeni wrote:

> I found some links to what look like much better archives. I'll start
> digging. Thanks as always Don!
> 
> I'm still hoping Etienne can expand a little bit on the densitometer density
> range bit of the converasation.
> 
> -Francesco
> 
> 
> On Sat, Oct 8, 2011 at 2:56 PM, Don Bryant <donsbryant at gmail.com> wrote:
> 
>> You can start with this one here below by former list member Carl Weese
>> (co-author of 'The New Platinum Print'):
>> 
>> 
>> http://theonlinephotographer.typepad.com/the_online_photographer/2010/04/the
>> -making-of-a-platinum-print-slideshow.html
>> 
>> 
>> 
>> -----Original Message-----
>> From: alt-photo-process-list-bounces at lists.altphotolist.org
>> [mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf
>> Of
>> Francesco Fragomeni
>> Sent: Saturday, October 08, 2011 5:34 PM
>> To: The alternative photographic processes mailing list
>> Subject: [alt-photo] Re: Your Approach to Making Negs for Platinum
>> Printing?
>> Ideal Negative Contrast and Dmax?
>> 
>> Don,
>> 
>> I must be looking inthe wrong places. I figured there must have been plenty
>> of this discussion before. I'll look through the archive link I have. Maybe
>> I have a weird link or I just want paying attention. I'll look through it
>> all again.
>> 
>> 
>> -Francesco
>> On Sat, Oct 8, 2011 at 2:29 PM, Francesco Fragomeni
>> <fdfragomeni at gmail.com>wrote:
>> 
>>> Etienne,
>>> 
>>> Wow! Thanks for all for all of the info. I'm only working with large
>> format
>>> negatives (I shoot 8x10 and larger) in this case so my follow up is in
>>> regard to what you posted regarding in-camera negatives and not the extra
>>> digital stuff.
>>> "Below are some observations I have made in the past (you will find
>>> others in the list archives, from me and others).  For the traditional Pt
>>> process, you want a negative with a density range ("DR") of 2.0 or higher
>> (I
>>> generally aim for 2.4) to get both Dmin and Dmax in the print.  Note that
>>> not all films available today will produce such a DR, no matter how you
>>> expose and develop them.
>>> BTW, I encourage everyone to stop speaking of "stops" and "contrast
>> range"
>>> -- much better to identify clearly what you mean and speak of "exposure
>>> scale" ("ES") and "density range" ("DR"), to make sure we are always
>> keeping
>>> the distinction in mind.  On this, see my message of 11 Oct 2009, in the
>>> archive.  For example, while the ES of traditional Pt is around 2.1 to
>> 2.4
>>> (and, therefore, a negative that produces a full-scale Pt print will have
>> a
>>> DR of 2.1 to 2.4), the full-scale DR of the Pt print itself is much lower
>> --
>>> only 1.4 to 1.7 (the latter only with heroic efforts)."
>>> 
>>> I definitely agree with what you're saying. I often get confused with all
>>> of the different terminology. When you say DR do you mean the range
>> between
>>> FB+F and the most dense tone in the negative? I have a X-Rite
>> transmission
>>> and reflection densitometer at home and I'm unsure of how to read a neg
>> to
>>> determine is DR or a prints ER. Is it simply reading most dense area and
>> the
>>> least dense area and taking the difference? My processes are always much
>>> more visual then technical but I'd like to grasp an understanding of how
>> to
>>> make all of these measurements so that I can empirically understand what
>> I'm
>>> visually seeing and doing.
>>> 
>>> I am specifically interested in figuring out how to properly measure the
>>> density range in a negative so that I can match my visual understanding
>> of
>>> what these negatives look like to the actual measurement of the negatives
>>> density range. I hope that makes sense. I suppose I'm just looking for a
>>> little clarification on the best practices for using a densitometer and
>> how
>>> to relate the measurements to density range and exposure scale.
>>> 
>>> Thanks so much for the help!
>>> 
>>> -Francesco
>>> 
>>> 
>>>> Francesco wrote:
>>>> 
>>>>  Now that I'm
>>>>> venturing fairly aggressively into platinum, I'm very interested in
>>>>> hearing
>>>>> how you all approach making your negatives for platinum. I'm speaking
>>>>> specifically about in-camera negatives (no digital negs or other
>>>>> processes
>>>>> here). Achieving the ideal contrast for platinum is what I'm interested
>>>>> in.
>>>>> For silver, a negative with a contrast range of around 3.5 stops will
>>>>> print
>>>>> well on a grade 2 filter or paper. There is also a ideal negative dmax
>>>>> that
>>>>> some people use as a standard to shoot for but I'm not sure what that
>>>>> number
>>>>> is. As I understand it, platinum calls for greater contrast to take
>>>>> advantage of the longer tonal range of the platinum process.
>>>>> 
>>>> 
>>>> Below are some observations I have made in the past (you will find
>> others
>>>> in the list archives, from me and others).  For the traditional Pt
>> process,
>>>> you want a negative with a density range ("DR") of 2.0 or higher (I
>>>> generally aim for 2.4) to get both Dmin and Dmax in the print.  Note
>> that
>>>> not all films available today will produce such a DR, no matter how you
>>>> expose and develop them.
>>>> 
>>>> BTW, I encourage everyone to stop speaking of "stops" and "contrast
>> range"
>>>> -- much better to identify clearly what you mean and speak of "exposure
>>>> scale" ("ES") and "density range" ("DR"), to make sure we are always
>> keeping
>>>> the distinction in mind.  On this, see my message of 11 Oct 2009, in the
>>>> archive.  For example, while the ES of traditional Pt is around 2.1 to
>> 2.4
>>>> (and, therefore, a negative that produces a full-scale Pt print will
>> have
>> a
>>>> DR of 2.1 to 2.4), the full-scale DR of the Pt print itself is much
>> lower
>> --
>>>> only 1.4 to 1.7 (the latter only with heroic efforts).
>>>> 
>>>> ==========
>>>> 
>>>> There are two things at work here: (i) matching the negative density
>> range
>>>>> ("DR") to the printing exposure scale ("ES"); and (ii) the character of
>> the
>>>>> exposure scale, however long or short it is.  If the DR of your negs is
>> too
>>>>> short to match the printing ES, you'll get low-contrast prints with
>> murky
>>>>> (but not very deep) shadows and/or fogged-looking highlights.  But even
>> if
>>>>> the negs have the right DR for the process, the characteristic curve of
>> the
>>>>> printing process may be ugly.
>>>>> 
>>>>> The standard long-scale Pt process has a very, very long linear scale
>>>>> with symmetrical, gently rounded toe and shoulder, typically printing
>> the
>>>>> whole step wedge with some scale left over.  Therefore, you need to use
>>>>> negatives with a very high DR to obtain all of the available print
>> zones
>>>>> with this process.  Photographers have not typically made negatives
>> this
>>>>> "bulletproof" since the late 19th Century, so folks have tried a number
>> of
>>>>> different methods to shorten the Pt exposure scale (adding dichromates,
>>>>> hydrogen peroxide, etc., etc.).  These tricks shorten the exposure
>> scale
>> by
>>>>> raising the threshold exposure -- not really a very promising way to go
>>>>> about it.  Anybody who has done serious sensitometry with the process
>> has
>>>>> seen the ugly characteristic curves the short-scale versions of the Pt
>>>>> process produce.  I have yet to see prints made using any short-scale
>> Pt
>>>>> process that came close to the look of "real" (long-scale) Pt prints.
>>>>> Unfortunately, so many workers are using the short-scale processes now
>> that
>>>>> many people don't even know what a good Pt print is supposed to look
>> like.
>>>>> 
>>>>> I commend to you an experiment:  Make some in-camera negatives with a
>> DR
>>>>> above 2.1 (try to hit 2.4 for starters), and print them using the
>> standard
>>>>> full-scale Pt process.  I bet you never go back to digi-neg Pt printing
>>>>> again, and depending on how big you think prints need to be, that you
>>>>> acquire one or more LARGE format cameras or learn to make good enlarged
>>>>> negatives in the darkroom (not so easy now that slow, blue-sensitive
>> copy
>>>>> films are long gone).  If you have no option besides digital, have a
>> service
>>>>> bureau make some 2.4 DR negatives with an imagesetter using your files.
>>>>> 
>>>> 
>>>> ==========
>>>> 
>>>> Think of it as mapping.  The scene you photograph has a certain range of
>>>>> luminance values.  You want to translate, or "map," these luminance
>> values
>>>>> to useful negative densities, which can in turn be mapped to the
>> available
>>>>> reflection densities of your chosen printing medium.
>>>>> 
>>>>> To do this, we start with the exposure scale ("ES") of the printing
>>>>> medium.  Using calibrated step wedges, we see what range of exposures
>> gives
>>>>> the full range of printed tones the medium is capable of producing --
>> any
>>>>> more exposure is indistinguishable from the blackest tone, and any less
>>>>> exposure is indistinguishable from the lightest tone (paper white, or
>> close
>>>>> to it).  Now, if we want the full range of tones the process is capable
>> of
>>>>> producing to be represented in our print [which may not always be the
>> case],
>>>>> we know that our negative must have a density range ("DR") equal to the
>>>>> printing medium's ES.  So, we arrange to translate the luminance values
>> in
>>>>> the scene to the particular negative densities that will produce the
>> print
>>>>> tones we want to represent each scene luminance value.
>>>>> 
>>>>> Not so long ago, we did this by adjusting our exposure and film
>>>>> development, and then perhaps reducing or intensifying the negative or
>>>>> masking it for printing, and finally by dodging and burning as we
>> printed.
>>>>> It sometimes took all that, because we have to condense or compress
>> the
>>>>> 1,000,000:1 luminance range of the scene we photographed (this is about
>>>>> normal for a sunlit scene) down to the 100:1 (or less) density range
>> that a
>>>>> print can reproduce.
>>>>> 
>>>>> These days, people who print digitally can use Photoshop to adjust the
>>>>> mapping from the as-captured (or as-scanned) image file to the negative
>> that
>>>>> will be used to make the print.  This is much easier, and also much
>> more
>>>>> flexible, than doing it chemically or with masks.  However, the goal is
>> the
>>>>> same -- to translate or map certain luminance values in the scene to
>> the
>>>>> desired print density values, using the negative as an intermediary.
>>>>> Applying curves is how we do this.  It's fundamentally the same as
>> using
>>>>> the Photoshop tonal controls (levels, brightness/contrast, whatever) to
>>>>> adjust a digital capture for the desired print values (i.e., if you are
>> just
>>>>> printing digital images on paper), with two added wrinkles: (i) you
>> have
>> to
>>>>> understand how the characteristic curve of the printing process
>> responds
>> to
>>>>> the negative values, and (ii) you have to be able to imagine how to "do
>> it
>>>>> in reverse" since you are working on a negative -- if you want the
>> shadows
>>>>> to have more contrast in the print, you have to increase the contrast
>> in
>> the
>>>>> lightest parts of the negative.
>>>>> 
>>>>> In theory, you can map any scene luminance value (or digital
>>>>> representation of a scene luminance value) to any available print tone
>> (with
>>>>> the caveat that the curve should be monotonic -- never reversing slope
>> --
>>>>> unless you are after special effects reminiscent of the Sabattier
>> effect).
>>>>> In my view, there is no substitute for learning enough
>>>>> sensitometry/densitometry to really understand how the mapping works,
>> and
>>>>> then to test your processes to see how they distort the mapping so you
>> can
>>>>> correct for it.  It's not very difficult, and once it is mastered you
>> will
>>>>> truly have the chops to get what you want out of your photographs.
>>>>> 
>>>>> So, all that said, back to curves destroying negative content.  Mapping
>>>>> is mapping -- the person who wants to represent the surface of the
>> earth
>> on
>>>>> a flat surface has choices to make, because there is no way to linearly
>>>>> reproduce the surface of a sphere on a flat surface.  And as we learned
>> in
>>>>> grade school, cartographers have come up with hundreds of different
>> ways
>> to
>>>>> do it, each one good for some particular task.  If you want to be able
>> to
>>>>> visualize comparative land areas, you use a different projection than
>> if
>> you
>>>>> want to determine bearings from one place to another.  The same is true
>> for
>>>>> mapping tonal values in photography.  So, the "right" curve is the one
>> that
>>>>> produces the results you want -- i.e., the one that maps the scene
>> luminance
>>>>> values to the print densities you want.  In general, one way I'd advise
>>>>> folks NOT to do this is to copy someone else's curve "because you're
>> using
>>>>> the same process."  No two people ever use the "same" alt process,
>> because
>>>>> there are way too many variables to control.  And no two monitors are
>> the
>>>>> same, or scanners, or printers, or Pt "emulsions," or coating
>> techniques, or
>>>>> anything else you use to make prints.  So, the only way to end up with
>> a
>>>>> useful curve for your process flow is to test and figure it out for
>>>>> yourself.
>>>>> 
>>>>> Generally, one would like to calibrate one's monitor, then build a
>> curve
>>>>> for each printing process one uses so one can just adjust the image on
>> the
>>>>> monitor (as a positive), then let the computer figure out what negative
>>>>> densities are required to map the monitor view to the final print
>> (though
>>>>> once again, the monitor has a considerably greater luminance range than
>> a
>>>>> print has density range, so it will be a "rendition" of the monitor
>> image,
>>>>> not a literal copy).  Only you can build such a curve, after doing the
>>>>> sensitometry/densitometry on your equipment and printing processes.
>> There
>>>>> are aids available, but IMO one is much better off gaining an
>> understanding
>>>>> of the fundamentals and just doing it -- just as people who really
>>>>> understood what they were doing always got better results than people
>> who
>>>>> "learned" the "zone" system by rote.
>>>>> 
>>>>> So, if you have a curve that really does translate (transliterate ??)
>>>>> from your monitor to your prints, great -- it is not destroying
>> anything,
>>>>> but rather helping you to map values from your digital image file to
>> the
>>>>> final print, thereby allowing you to do your image adjustment by eye
>> rather
>>>>> than by figuring.  But if your curve doesn't produce prints that are
>>>>> pleasingly rendered based on the screen image, you need to change
>> something.
>>>>> You can futz around with the process to try to match it to the curve
>> you
>>>>> have, but that's the hard way (and you may well not ever find a
>> variation
>>>>> that works as you'd like).  Better to adjust your printing process
>> until
>> you
>>>>> get the most linear scale you can (for reasons I won't go into here,
>> having
>>>>> to do with producing the smoothest tonal range), then developing a
>> curve
>>>>> that translates from your monitor to your prints.
>>>>> 
>>>>> The problem with the "short-scale" versions of Pt is that they have
>> much
>>>>> less linear tonal ranges than long-scale Pt.  You can successfully map
>> this,
>>>>> if you work at it, and thereby get correct overall tonal rendering by
>> using
>>>>> a curve that compensates for the nonlinearity.  However, you still
>> won't
>> get
>>>>> the smooth transitions that long-scale Pt can produce.  And since the
>>>>> gorgeous tonal rendering is the real draw of Pt in the first place, why
>>>>> settle for something less just because one would prefer to avoid
>> dealing
>>>>> with how to make digital negatives of sufficient DR?  Particularly
>> given
>> the
>>>>> cost of the Pt process, I just can't see why one wouldn't use it to its
>> full
>>>>> advantage -- which IMO requires using the long-scale process.
>>>>> 
>>>> 
>>>> 
>>>> Best regards,
>>>> 
>>>> etienne
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> ______________________________**_________________
>>>> Alt-photo-process-list |
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>>>> 
>>> 
>>> 
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