[pure-silver] Re: Oriental Seagull Papers

September 21, 2007, from Lloyd Erlick,

Thank you!
--le





At 12:07 PM 9/20/2007 , you wrote:
>"Lloyd Erlick" <lloyd@xxxxxxxxxxxx>
>> "Nicholas Lindan"
>> > Ink jet can't do _real_ shadows and possibly never will.
>> ... could you elaborate a bit?
>
>It's in the math, simplified it goes like:
>
>Postulate a 300 pixel/inch printer laying down 
>black ink at 3000 dots/inch.
>
>Each pixel is 10 x 10 dots, or 100 dots/pixel.
>
>If, for an otherwise all black pixel, we calculate:
>
>White    Black   Reflects  OD
>Pixels   Pixels  
>   0      100    0.01      2.00
>   1      99     0.02      1.70
>   2      98     0.03      1.53
>   3      97     0.04      1.40
>   4      96     0.05      1.30
>   5      95     0.06      1.23
>  10      90     0.11      0.96
> 100       0     1.00      0.00
>
>There are only 3 tones between shadows at 1.3 OD and black.
>
>And these 3 tones only exist in theory:  All the printers I 
>have tried can't leave one dot white in a sea of black.
>
>The software that drives IJ printers gets around this by 
>increasing the size of the dark pixels - lowering resolution, 
>by using colored ink to make a grey so the print changes
>tones and/or color in different light, and dithering the dots 
>so a uniform sea of grey pixels is a random sea of dots 
>rather than an array of pixels with x dots in them.
>
>Printers advertised for black and white have several shades
>of grey ink and ink companies sell special black & white ink
>sets.  'Photo Black' is becoming more common in printers.
>
>--
>Nicholas O. Lindan
>Cleveland Engineering Design, LLC
>Cleveland, Ohio 44121
>
>===========================================================================
==================================
>To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you
subscribed,) and unsubscribe from there.
> 

=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your 
account (the same e-mail address and password you set-up when you subscribed,) 
and unsubscribe from there.

Other related posts: