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Digital BW, The Print

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RE: [Digital BW] Optimal DPI

2003-03-02 by Austin Franklin

Hi Bob,

> I think you said 44", which is the OS print limit, not the PS print limit.
> Not much difference in actual size, but it is a different limiting factor,
> it seems.

I know about the PS 30,000 pixel limit (which I find really silly), but I'm
unaware of what any other limits may be.  I know when using Cone Piezo, I am
limited to 44" on my 3000, and that is using PS...

> > What about if you set the PPI to 100 and try 100"?
>
> OK, you can set the image size to be 100" long at 100ppi, but
> when you go to
> print from PS, the last but one print dialog limits the height of
> the image
> to 41.667" because it 'knows' that it will be upsampled to 720
> ppi,

What is the "it" that knows?  Shouldn't be PS, but the printer driver,
right?

> so only
> part of the image would be printed, and the 'size exceeds printable area'
> dialog popped up when I went on.

Been there, done that.

> No way round it in PS, since image size in PS is limited to 30
> 000 pixels in
> one dimension, so if you enter image size as 400" at 100ppi (40
> 000 pixels)
> an error box pops up saying the upper limit is 300".

OK.  So, let's see what the limits are.  PS is 30,000 pixels, which has
nothing to do with the printer driver or anything else.  The Epson printer
driver has a limit, which you say is 41.667"???  Where does that limit come
from?  If you use a different application, is that limit different?

Now onto the OS limit...apparently there is some limit, since the Cone
driver can't go above 44"...but Cone blamed that on Epson, and the physical
hardware...so I don't believe that is an OS limit, but an Epson
hardware/command set limit...which is probably why the driver has a limit.

If I remember right, that 44" limit of the hardware is based on an internal
counter in the hardware.  This should be easy to figure out why.  The
printer steps a 1/360 of an inch, so 44 * 360 = 15840...which looks to me
like they are limited by some internal counter to 14 bits, though the paper
size command does show 16 bits can be used, but that is printer independent,
and possibly the 3000 has a firmware max of 14 bits in and of it self.

I'll bet if we check the Epson command set, it'll say that somewhere.  I did
find in the 4ch_98b command set document, that the 3000 has a maximum
printable height of 15,599 dots, assuming 1/360" dot size (p. 21).  So, it
sounds to me like this is not an OS limit, but a printer hardware limit.

Regards,

Austin

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