Re: Sharpness, contone (was Re: Useful results from gum tests

Katharine, there are half-tones and halftones. I used a random grain
halftone screen that I made myself using an Tri-X negative enlarged onto
sheet film. I can't remember the exact details, but I think it was
important to get it just slightly out of focus. It wasn't my idea, I
think I got it from Arnold Gassan's book but I could be wrong. When we
now print a neg using an inkjet, that neg is a halftone image rather
than a continuous tone image, and can print pretty well.

Your test simply shows that 600dpi laser printers are pretty useless at
producing halftones, which I think we all knew. You only need to try
printing a photo on a laser printer after all. Had you used a 3000 dpi
device the results would have been of more interest, whether you had
chosen to print a regular or random halftone.

However these images are easy to print, and I used to get students using
paper negs from the laser to print gums, as they could then develop them
rapidly by hosing them down with hot water. Exposure is also far less
critical, and it is pretty hard to overexpose.

I greatly admire Terry's skill in developing his delicate images and
wasn't in any way trying to knock it when I said I chose to do things
the easy way.

Peter Marshall
petermarshall@cix.co.uk
_________________________________________________________________
My London Diary http://mylondondiary.co.uk/
London's Industrial Heritage: http://petermarshallphotos.co.uk/
The Buildings of London etc: http://londonphotographs.co.uk/
and elsewhere......

Katharine Thayer wrote:
>
> On Apr 12, 2006, at 8:29 AM, Katharine Thayer wrote:
>>
>> There's a page on my website that compares continuous tone to a
>> stochastic dot for printing gum. It's not quite the same as
>> halftone, which is what Peter was suggesting the other day would be
>> the best kind of negative for gum, but it does address the more
>> general question of whether dots are better for gum than continuous
>> tone.
>>
>> http://www.pacifier.com/~kthayer/html/dotcont.html
>>
>
> I should specify that the stochastic dot here is from a bitmap file;
> the reason I used bitmap is that I did the test prints shown on that
> page in response to a statement made here that a stochastic bitmap was
> better for gum than continuous tone.
> kt
>
Received on Wed Apr 12 12:24:50 2006