At 06:28 AM 2/24/98 -0800, Beakman wrote:
>> I, too have been working with Island Imaging. Scott Blaylock is
>> definitely a great guy to work with. He REALLY wants to make this work.
>> However, I am using Fokos' method for digital negs, rather than
>> Burkholder's. So far, they have been experiencing banding problems with
>> this output and are still trying to work out a fix. I'll post again to
>> the list as soon as I get a good negative from them. I think it's only
>> a matter of time.
>>
>> Kerik
>
>
>I am assuming that the banding you are experiencing is primarily in the
>highlights. The key here is to:
>
>a) tweak the compensation curve to match your particular paper/coating
>method/developer combination
>
>and
>
>b) get the exposure of the digital negative correct. You may think "but
>they're just black dots", but this is not true. The negative acts like a
>hybrid analog/digital negative and it is important that the density of
>the negative be correct in order to mate correctly with the
>characteristic curve of your paper.
>
>Because you are trying to match a an irregular curve moving a little in one
>direction or antother along the curve will create a mismatch, and hence
>banding.
>
>To help you visualize this, consider a graph of the characteristic curve
>of your paper. Next, cut a piece of cardboard to match this curve. Mark the
>10% point on the cardboard curve. Now move align the point you just
>marked with the 15% point on the graph -- this represents making a
>digital negative too dense (for a correctly exposed negative the 10% mark
>of both the cardboard and the graphe would line up). With the 10% and
>15% marks aligned you will note a curve mismatch -- you won't be able to
>get both curves to match along their entire lengths. The points where
>the two curves diverge can lead to banding.
>
>c) Banding can sometimes be caused by the type of line screen used --
>round dot, for exapmple has banding near 50%, elliptical dot in other
>areas. The differently shaped dots were all developed to help this
>problem. There are even some special linescreen patterns which change
>shape depending on the density.
>
>d) Print so that your 1% dot prints paper white. Do not have any 0% dot
>areas in your negative.
>
>e) In my image file I make the very lightest, non-pure-white tone have at
>least a 7% density (this is before the platinum compensation curve is
>applied).
>
>Good luck!
>
>David
>
>
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