Re: What are the advantages of using Cyanotype as the first layer fortri-color gum prints? Paper Problems...

Hi Loris,

That is just about as good as it gets in terms of printing detail. I have
used that target to test a lot of output devices including high end laser and
LED printers and have had only a few printers able to come somewhat close in
printing the 1 x1 pixel sharpness grid—although they can usually print the
vertical and horizontal one pixel line pairs. One issue that affects this is the
dithering pattern of the printer driver. Since the software is also looking
at neighboring pixels to determine how to print a specific pixel and give a
smoother transition between pixels, the checkerboard goes blurry. To avoid
this affect, you can use bitmap mode to get the printer to print sharper detail—
though the Photoshop bitmap mode also does a similar "glance" at neighboring
pixels to a certain extent.

I used these sharpness grids to confirm for myself that 360 ppi was the
optimum file resolution to send to a printer for sharp detail. I used resolutions
such as 240, 300, 360, 480, & 720 ppi. Though there is some discussion that
the Epson desktop models are "720 ppi" printers and the Epson large format
printers are "360 ppi" printers, I did not find that sending a 720 ppi file to a
desktop model improved detail printing.

The results you get will also depend on the smoothness of the paper you are
using with the process. I think Sandy King may have done some tests on this.

It's amazing how much an image will diffuse if you don't have perfect contact
between the emulsion side of the negative and the coated paper. It's easy
to see this by printing a negative upside down with the emulsion side up. Just
the thickness of the Pictorico OHP film makes a lot of difference.

Best Wishes,
Mark Nelson
Purchase the eBook & PDN System for Your Own Custom Digital Negative Workflow
@
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www.MarkINelsonPhoto.com

In a message dated 9/19/05 12:16:21 PM, loris_medici@mynet.com writes:

>
> Well, I can tell that my recent Cyanotype 2 prints on HP Cot320 paper are
> extremely sharp; using 2880dpi Epson 1290 (1280 in the States) digital
> negatives made on Ultrafine Crystal Clear, lightsouce: 8 BL tubes spaced
> 1.5cm (5/8") from each other, distance to contact frame glass 3.5cm (1
> 3/8"). Prints are so sharp that you can clearly and cleanly see every square
> of the 2x2 pixels checkerboard pattern printed at 360dpi! (And I'm sure it
> would also show a clean 1x1 pixel pattern also - if the printer was capable
> to print it cleanly... Unfortunately it's not.)
>
> Do you think that gum is capable of making prints rivaling / surpassing this
> resolution?
>
> TIA,
> Loris.
>
Received on Mon Sep 19 12:03:21 2005