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Author Topic: Resizing up or down for printing, what is the tipping point?  (Read 1427 times)

BartvanderWolf

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #20 on: February 03, 2018, 09:19:26 AM »

But, if there isn't a driver option to make use of 1200 PPI then yes if the image is over 600 PPI you would want to downsample in Photoshop and then output sharpen.

I agree. It's better to have control over the conversion, and add output-sharpening to compensate for resampling losses and specific media features (ink diffusion or contrast).

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For Epson the magic numbers are 360/720 PPI.

In general, that's correct. However, there are recent Epson models that seem to be using 300/600 PPI, just like Canon and HP. An application like Qimage would detect (and use) that automatically because it interrogates the printer driver for those details.

Cheers,
Bart
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NAwlins_Contrarian

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #21 on: February 03, 2018, 11:04:01 AM »

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While I got a bit of a laugh to be renamed Bruce, my name is Jeff.

Doh! First, please accept my apology for making that mistake.

Second, just in case you were wondering, Schewe is not a common name around here, I only know one, and his name is Bruce. Apparently my end-of-the-day brain wasn't up to keeping it straight.
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datro

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #22 on: February 03, 2018, 05:06:03 PM »

... Afterall, scanning is not very fast either.

Cheers,
Bart

Hi Bart,
Yes, you are quite right  :).  Scanning a 4x5 negative on my Howtek 4500 @4000dpi takes about 1hour 10 minutes.  But the results are worth it, and I can do other work in parallel so it is not wasted time.

Thanks very much for your thoughts and suggestions (and also the previous work on your ImageMagick script!).  Much appreciated.

Dave
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Doug Gray

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #23 on: February 03, 2018, 10:19:05 PM »

As part of resampling, the diffusion dithering, more so than the ink dot size, that occurs spreads the location of a printed pixel a bit. This creates a low pass filtering effect similar to the "zero hold" low pass filtering that occurs with a DTOA output is held constant between clocks.  On the "zero hold" DTOA it produces about a 4 dB drop at Nyquist. The dithering, or pixel spreading, is a somewhat larger effect that occurs but can also be measured.

I ran an experiment with Canson Rag Photo on my 9500II and there is about a 5 dB drop off at 250 PPI and 2 dB at 150 PPI when printing 600 PPI images with the finest setting. It seems possible that this characteristic could be measured for a given printer and an appropriate sharpening filter applied. There are limits to such a filter. Pixels that would be pushed beyond the media white or black would have to be spread out so one couldn't completely compensate though I believe that rare in most real photos.

I'm also curious whether glossy is better.
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tom b

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #24 on: February 03, 2018, 11:26:52 PM »

Michael did a test with prints from two widely different cameras. The results were very interesting

Please, do two prints (or more), ask people if you can tell the difference between the two and report back. I know what the results should be, but I'm willing to be surprised.

Cheers,
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Tom Brown

unesco

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #25 on: February 04, 2018, 03:00:39 AM »

Yes, moire is often visible when high res image is downsampled by Epson driver. When I saw it the first time I could not find a reason and it have taken me a while to locate the problem.

As for QTR (up/down)sampling - you can try using a file just you have since QTR does spline sampling process to 720 ppi which works fine.
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texshooter

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #26 on: February 11, 2018, 08:37:12 PM »

Interesting twist.  Vincent Versace says you should print at 270ppi, which is 90ppi lower than the printer's native 360ppi resolution (Epson), when

1. You have a bronzing problem, or
2.  When using papers with high dot gain absorption (eg, Epson Somerset Velvet)

video,  start 32:15
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Schewe

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Re: Resizing up or down for printing, what is the tipping point?
« Reply #27 on: February 12, 2018, 04:53:36 PM »

Vincent Versace says you should print at 270ppi, which is 90ppi lower than the printer's native 360ppi resolution (Epson)...

Vinnie is wrong.
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