[filmscanners] Re: Epson Printing Post Scanning...continued

["Arthur Entlich" <artistic-1@shaw.ca>]

Hi Simon,


On the one hand, there are 4 fingers and a thumb ;-)...

This is one of those situations that could be answered "Yes, it's all a
matter of numbers", but the question is which numbers one is going to
consider.  With enough information, I'm sure someone could plug the
numbers into an equation and determine which scanner causes more
aliasing of grain.  The number of elements on the CCD only provides part
of the picture.  The size of the actual element, and the distance
between each element are also important determining factors, and further
is the fact that the image is "projected" onto the CCD sensor, so the
ratio of magnification, and the area of the CCD sensor that is engaged,
determines the optical "dpi" numbers.  Therefore, dpi tells you more of
the story than the total number of elements per CCD line.  The next
matter is the size of the grain or grain clouds of the film involved.

At the end, there is a soup of numbers that probably can be plugged into
an equation and result in the answer you are seeking, but I sure don't
know the numbers or the equation ;-).

However, in general, at least from the empirical, it appears scanners in
the 2400-2900 dpi ranges tend toward increasing grain aliasing problems
with average film grain sizes, while those of about 4000 dpi are less
problematical.

Perhaps some others here can add to or further discuss this matter.

Art

Simon Lamb wrote:

> Art
>
> Are you saying that 3 x 10,000 element CCDs are better at reducing grain
> aliasing than 3 x 8000 element CCDs for example?  Do any other parts of the
> scanner make a difference or is it purely the number of elements 'reading'
> the film?  I guess the logical conclusion is that some of the more expensive
> scanners, such as the Flextight Photo (3 x 8000 CCDs/3200ppi) will produce
> more grain aliasing than the current crop of 3 x 10,000 CCDs/4000ppi
> scanners.  If that is the case, why would anyone buy the Photo for example.
>
> Simon
>
> Arthur Entlich wrote:
>
>
>>I'll reply to you in more detail in private mail.
>>
>>One of the principle advantages of the 4000 dpi native resolution is
>>that it should reduce grain aliasing due to the frequency of the CCD
>>elements relative to film grain.
>>
>>Film grain seems to be aliased by scanners in the 2400-2900 dpi range
>>due to its frequency.  Sure some films would be more likely to manifest
>>it during scanning since not all film has the same grain or dye cloud
>>size, and newer films would tend toward smaller grain, but I have found
>>overall that the SS4000+ (and I assume this is due to the resolution
>>more than anything else), has little to no grain aliasing.
>>
>>As Kennedy has discussed, grain aliasing is also reduced if the correct
>>use of optical filtering occurs, which in this case would be slight
>>defocusing.  Have you attempted very slightly defocusing the original
>>scan and then using unsharp masking to recover the focus of the correct
>>frequency ranges, as he suggested?
>>
>>Art
>>
>>HMSDOC@aol.com wrote:
>>
>>
>>>I think my problem in producing prints is grain aliasing.  It seems
>>>
> worse on
>
>>>some films compared to others, when I look carefully I can see it in the
>>>
> scan
>
>>>and sharpening tends to make it worse.
>>>
>>>Assuming that is what it is, then what is the best way to deal with it,
>>>
> fix
>
>>>it, or avoid it.  Do different brands of 4000 dpi scanners tend to
>>>
> accentuate
>
>>>the problem more than others?
>>>
>>>Howard
>>>
>
>
>
>


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