Re: How to apply curves in PS for digital negatives...

Excellent--thank you. I find that you can also go to
image,adjustments,posterize, and a dialog box will let you type in the
number of steps. Grace
On Saturday, November 26, 2005, at 04:03 PM, John Brewer wrote:

> In CS I would use the posterize edges filter (filters>artistic>poster
> edges), varying the posterization slider to get the required number of
> steps.
>
> J
>
>
> www.johnbrewerphotography.com
> ----- Original Message ----- From: "Grace Taylor"
> <gtay22@earthlink.net>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Sunday, November 27, 2005 4:51 PM
> Subject: Re: How to apply curves in PS for digital negatives...
>
>
> In order to develop the appropriate curve for your printer, ink, and
> substrate, print a step tablet on the same transparency as your image,
> and apply the same curve to the step tablet. That way, you can see
> where your curve needs adjusting to change the contrast.
>
> There is an easy way to produce your own digital step tablet by
> opening a new window the size you want for your step tablet then use
> the gradient tool straight across the window, from black to white.
> Check in the info pallet to be sure the ends are 100% and 0%. I made
> and saved a 21 step tablet this way for VD printing. In Photoshop
> there is a way to indicate how many steps you want, but unfortunately
> it is not in the same place in CS2 as it was in 7, so I can't pass
> along that step. Anyone else know where it is?
>
> Grace.
>
> On Sunday, November 27, 2005, at 11:14 AM, Michael Koch-Schulte wrote:
>
>>>> Christina wrote:
>>>>> I´ve found this site, where you can download some sample curves for
>>>>> PS for making digital negatives.
>>>>>
>>>>> http://www.alternativephotography.com/articles/art051.html
>>>>>
>>>>> But how to use them?
>>>>>
>>>>> I mean do I first convert the image to a negative and then apply
>>>>> the
>>>>> curve, or first apply the curve and then convert into a negative?
>>>>>
>>>>> The result is different.
>>>>>
>>>>> Thank you very much for your help,
>>>>>
>>>>> Lg
>>>>>
>>>>> Christina
>>
>>>> Christina,
>>>>
>>>> First, make your adjustments to your image. Second, apply your
>>>> chosen curve. Third, convert to negative. You will also want to
>>>> flip the image horizontally either in PS or in print setup.
>>>
>>> I guess where my misunderstanding lies is that the curve for Van Dyke
>>> removes some of the contrast of the image. I definitetly need to
>>> increase the contrast to make a proper Van Dyke image. I have yet to
>>> get an acceptable digital negative, but continue trying.
>>>
>> I look at many of the curves in the curves area of
>> alternativephotography.com and just roll my eyes. Half of them look
>> totally
>> wrong to begin with and other half give you no details on how there
>> were
>> produced, what printer, what paper, inks, times et al. No one has
>> mentioned
>> so far, although it's been said many times, that applying a generic
>> curve
>> like this will probably only produce mediocre results -- if you're
>> lucky. To
>> truly reap the benefits of the curve function you have to print YOUR
>> OWN
>> step tablets so you can match the tones from your output (i.e. the
>> final
>> VDB) to the tones produced on your digital negative output. For all
>> you know
>> this curve was a VDB produced on a piece of paper towel and developed
>> in
>> creek water. Nothing wrong with that except that maybe it's not your
>> brand
>> of paper towel or you live on a different creek. You need to learn
>> how to
>> produce your own curves. You can buy into someone's system or develop
>> your
>> own as I did. For starters, get a piece of graph paper and map out
>> where 5,
>> 10, 20, 30...80, 90, 95 and 100 per cent black on your negatitve
>> printed on
>> your final output. What you'll find is that the relationship is not
>> linear.
>> Create a table from your results and make a curve based on that. This
>> is
>> where understanding of the process begins.
>>
>> ~m
>>
>>
>>
>
Received on Sun Nov 27 11:46:48 2005