From: Grace Taylor (gtay22@earthlink.net)
Date: 04/23/03-11:44:25 AM Z
on 4/23/03 12:09 PM, Bill Marsh at redcloud54@earthlink.net wrote:
> Grace Taylor wrote:
>>> After
>> making some calculations for changing the densities in the step tablet, I
>> used the transfer function to create a new curve and printed an adjusted
>> image and step tablet as before. This also was not right, but the third
>> adjustment using the transfer function was right and I was able to get good
>> negatives and good Vandyke images.
>>
>
> What calculations did you make?
>
> Bill
>
Well, a better word would be guesses. Anyway, perhaps the best way to
explain what I did is to give you the numbers. I didn't save the platinum
curve so I don't have those values, but I think the numbers from my first
adjustment to the third and final adjustment will illustrate the process. I
use a step tablet in increments of 10 percentage points. For my first
adjustment curve, I entered in the transfer function 5, 13, 17, 21, 25, 29,
34, 38, 42, 53, and 95 for the values 0, 10, 20, 30, 40, 50, 60, 70, 80, 90,
and 100. There was not enough separation in the lower and higher values, so
the curve was adjusted with these values - 6, 15, 18, 21, 25, 29, 34, 38,
46, 58, and 96. The percent adjustment was guess and intuition based on the
difference in appearance of the printed step tablets and the images. I hope
this helps. Grace
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