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

Kees Brandenburg workshops at polychrome.nl
Sun Oct 9 13:17:08 GMT 2011 

Hi Francesco,

Copies of the old and the new archives are here:

http://altphotolist.org/

kees



On 9 okt. 2011, at 00:52, Francesco Fragomeni wrote:

> Also, so you can all see what I'm seeing, below are the archives I am able
> to find:
> 
> http://lists.altphotolist.org/pipermail/alt-photo-process-list/ November
> 2009 - Today
> http://www.usask.ca/lists/alt-photo-process/ 1994- August 2006
> 
> I cannot find any archive containing the gap between August 2006 and
> November 2009.
> 
> -Francesco
> 
> On Sat, Oct 8, 2011 at 3:20 PM, Francesco Fragomeni
> <fdfragomeni at gmail.com>wrote:
> 
>> My issue is that most of the information I'm finding is just speaking in
>> general terms rather then specific empirical measurements. Most sources talk
>> about increasing development to achieve greater contrast or exposing one way
>> or the other. All of that is nice but lacks any actual measurements. Now I'm
>> very visual in how I work but having numbers to back you up can really be
>> quite effective in reinforcing the visual decisions being made. Thats why
>> I'm interested in ideal density numbers for platinum and its why some of the
>> points Etienne touched on were of interest to me. I know I need a neg with
>> more contrast and I know how to achieve that. I'm trying to get away from
>> generalities. I want to know actual density measurements so that I can use
>> my densitometer to read my negs to confirm that I am achieving what I want.
>> I'm trying to use the empirical measurements as a reinforcement and
>> supplement to my visual process.
>> 
>> I hope that makes sense and I don't sound crazy.
>> 
>> -Francesco
>> 
>>  On Sat, Oct 8, 2011 at 3:12 PM, Francesco Fragomeni <
>> fdfragomeni at gmail.com> 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 |
>>>> http://altphotolist.org/**listinfo<http://altphotolist.org/listinfo>
>>>>>> 
>>>>> 
>>>>> 
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