Re: Flat Negatives

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From: Bill Marsh (redcloud54@earthlink.net)
Date: 04/24/03-11:02:10 AM Z


Thanks, Grace, for the demystification.

Regards,

Bill

Grace Taylor wrote:
> 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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