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Author Topic: Printing at 300dpi, 360dpi or what  (Read 38793 times)

texshooter

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Re: Printing at 300dpi, 360dpi or what
« Reply #40 on: October 23, 2011, 09:04:56 am »

I will try to test some other image tomorrow, this time an image that is above 300ppi.


How did your second experiment work out?
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RFPhotography

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Re: Printing at 300dpi, 360dpi or what
« Reply #41 on: October 23, 2011, 10:53:26 am »

Jeff, just for the sake of absolute clarity, are you talking about upsampling in the LR Print module using the Print Resolution option or by exporting the file to a new version and using the upsampling in the Export dialogue, then printing that file? 

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Geraldo Garcia

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Re: Printing at 300dpi, 360dpi or what
« Reply #42 on: October 23, 2011, 01:53:18 pm »

How did your second experiment work out?

I did not have the time to perform the test yet, unfortunately. But I will do it for sure and will let you know.

Best regards.
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Schewe

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Re: Printing at 300dpi, 360dpi or what
« Reply #43 on: October 23, 2011, 03:21:40 pm »

Jeff, just for the sake of absolute clarity, are you talking about upsampling in the LR Print module using the Print Resolution option...

Yes...that's one of the advantages of printing from Lightroom–you can check the native resolution with the Dimensions guide option and see what the resolution is at the print size and then decide what output resolution to use. This avoids having to spawn off multiple files for various print sizes...
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RFPhotography

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Re: Printing at 300dpi, 360dpi or what
« Reply #44 on: October 23, 2011, 03:35:32 pm »

Thanks, Jeff.  That's what I figured.  One of the nice efficiencies of LR.  Just wanted to check to be sure I wasn't missing something.
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Geraldo Garcia

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Re: Printing at 300dpi, 360dpi or what
« Reply #45 on: October 24, 2011, 10:40:40 pm »

How did your second experiment work out?

Today I managed to find some time to continue my experiment about resampling and printing from LR and QImage.
This time I found an image that would have 450ppi at my chosen print size, the exact middle between 300 and 600ppi (my printer is a HP Z3200). I printed it 5 times on the same paper as before (Canson Photo Satin Premium RC 270g), on the following order:

1) Printed without up-sampling or output sharpening at 450ppi
2) Printed from LR3.5 down-sampling to 300ppi with "standard glossy" print sharpening
3) Printed from LR3.5 up-sampling to 600ppi with "standard glossy" print sharpening, printer set to "maximum quality"
4) Printed from Qimage down-sampling to 300ppi with "standard - 5" print sharpening, "fusion" interpolation
5) Printed from Qimage up-sampling to 600ppi with "standard - 5" print sharpening, "fusion" interpolation, printer set to "maximum quality"

This time the game was more levelled. The image was a portrait with crisp sharp focus on the eyes, eyelashes and part of the hair and skin. The model had almost no make up, so de pores and the skin texture are quite evident on the crisp focus areas. At the same time the image also has a shallow depth of field and I was curious to see how the output sharpening routines would handle those areas, as one of the things I hate the most is sharpening artifacts on out-of-focus areas. Both QImage and LR 3.5 output sharpening hadled those areas very nicely without any image degradation.

The (1) was the worse, not bad actually, but below the others in terms of image detail and sharpness. All the other four images are excellent and almost identical to the naked eye. Looking very closely  we can rule out number (2) also, but that is almost a stretch. The other three images (600ppi from LR and 300 & 600ppi from Qimaqe) are tied without hope of finding a winner.

This findings are somehow consistent with the opinions of some colleagues that is better to up-sample and apply output sharpening when printing from LR 3.5 or QImage. Again QImage produced an interesting anomaly, this time the down-sampled image being as good as the up-sampled one.

The next experiment will be the same thing on mat rag paper.

Best regards.
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Schewe

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Re: Printing at 300dpi, 360dpi or what
« Reply #46 on: October 24, 2011, 11:45:52 pm »

The next experiment will be the same thing on mat rag paper.

Yeah well, I would guess that a matte paper will top out with 300PPI with output sharpening...I doubt there's much to be expected or extracted from upsampling for matte/watercolor papers. in fact, some matte/watercolor papers won't even allow setting a max output (this is more specific to Epson, can't be sure about Canon/HP).
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Geraldo Garcia

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Re: Printing at 300dpi, 360dpi or what
« Reply #47 on: October 25, 2011, 01:02:07 am »

Yeah well, I would guess that a matte paper will top out with 300PPI with output sharpening...I doubt there's much to be expected or extracted from upsampling for matte/watercolor papers. in fact, some matte/watercolor papers won't even allow setting a max output (this is more specific to Epson, can't be sure about Canon/HP).

Sure Jeff, I tend to agree, but will try 600ppi also just to see what happens. I think HP allows the setting, but never actually tested it.
Will see!
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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #48 on: October 25, 2011, 05:18:16 am »

Sure Jeff, I tend to agree, but will try 600ppi also just to see what happens. I think HP allows the setting, but never actually tested it.
Will see!

Hi Geraldo,

There is a benefit to be had from first upsampling to 600 PPI, doing good sharpening at that output resolution, and then print, even if the output medium won't resolve the finest detail. The benefit is that when sharpening the highest spatial frequencies (the ones that don't resolve due to the medium), the next lower spatial frequencies (the ones that do resolve on the medium) also get a boost but without the artifacts. When you know that the finest details cannot be resolved by the medium, then you can push the highest frequency sharpening a bit further than usual.

Cheers,
Bart
« Last Edit: November 13, 2011, 04:16:50 am by BartvanderWolf »
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narikin

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Re: Printing at 300dpi, 360dpi or what
« Reply #49 on: October 25, 2011, 08:18:37 am »

There is a benefit to be had from fist upsampling to 600 PPI, doing good sharpening at that output resolution, \

Hi Bart, just out of interest, which program are you using/recommending to upsample? 

I have a good MF digital file to make a large print (about 147x190cm). Uninterpolated it is a sweet 120dpi exactly, upsampling this to 360dpi before applying my sharpening routine and sending to the printer, is what is suggested here, but PS does a so-so upsizing.  What are people suggesting?  I could use Qimage with 'output to file', and then do my special sharpening, but it balks at such large output, hitting 32bit memory limits,  even with an 8bit file. So that's off the list.
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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #50 on: October 25, 2011, 11:46:43 am »

Hi Bart, just out of interest, which program are you using/recommending to upsample?

I use different routes, different pograms, depending on the rest of the workflow. 

Quote
I have a good MF digital file to make a large print (about 147x190cm). Uninterpolated it is a sweet 120dpi exactly, upsampling this to 360dpi before applying my sharpening routine and sending to the printer, is what is suggested here, but PS does a so-so upsizing.

Actually, Photoshop's Bicubic Smoother isn't all that bad, because it doesn't create too many artifacts which sharpening will only 'enhance' further. It does require, and can stand, some additional sharpening, Smart sharpening (Lens Blur, more accurate) at least. Better deconvolution sharpening would be ideal, but it might take a while to execute (processor intensive).

Another option is to use ImageMagick which by default uses the Mitchell Netravali type of reconstruction filter for upscaling, and it allows to optionally modify the settings depending on how sensitive the source data is for generating (e.g. ringing) artifacts. However, ImageMagick's command line driven interface isn't everybody's cup of tea.

Another option is to use Photozoom Pro which allows to boost sharp edges as rasterless vector data (a bit similar to the Blow-up plug-in) but less expensive. One needs to exercise restraint in applying the edge enhancement, because it can lead to a mental disconnect between the representation of edges and surface detail, which IMHO looks unnatural.

However, these may all may cause file size issues further down the chain, except Photozoom Pro. Photozoom Pro also works as a Photoshop plugin, so it could be used when one prints remotely direct from Photoshop, and PhotoZoom Pro 4 enlarges images up to 1 million by 1 million pixels.

Quote
I could use Qimage with 'output to file', and then do my special sharpening, but it balks at such large output, hitting 32bit memory limits,  even with an 8bit file. So that's off the list.

I have understood that it's not a direct Qimage problem, but a potential problem with the TIFF library specification. TIFFs are limited to 4GB file sizes due to its 32-bit adressing method. Some libraries are written with signed integers, and are therefore limited to 2GB file sizes. The upcoming BigTIFF standard is not final yet. It would be a nice addition if Qimage could write Photoshop PSB files, but that would probably lock the output files to Photoshop only as printer driver, which wouldn't seem to benefit Mike Chaney much especially since it forces him to change his code when the PSD proprietary (?) format is changed, so I can understand his hesitation. A 64-bit Qimage version appears to be scheduled for later in 2012, but that is not necessarily coming with a large file output option.

Which leave us with printing directly from Qimage, and that should work fine given the fact that all conversions (colorspace and interpolation) are handled on a block by block basis, which are then immediately fed to the printspooler. Since Qimage also allows to tweak the amount of Smart Sharpening it applies after resampling, it seems like a good compromise. For remote printing it may not be possible to persuade them to use Qimage, which would lead us back to one of the earlier options mentioned.   

Cheers,
Bart
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texshooter

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Re: Printing at 300dpi, 360dpi or what
« Reply #51 on: October 25, 2011, 12:35:44 pm »

Is it better to sharpen AFTER a QImage resample using QImage print sharpening than it is to sharpen with Photoshop (or PhotoKit sharpen)?
I'm hearing a lot of complaints that Qimage doesn't allow print sharpening with other tools besides Qimage, unless one first saves a copy of the file as a TIFF. But doing that contravenes the whole point of not having to spin off separate resampled files to the printer. What if someone needs more selective sharpening application than the QImage's Low, Med, High sharpening setting will permit?

Or is it better to use the QImage sharpening tool because it is more optimized for it's upsampling algorithm. In other words, will Photoshop sharpening monkey up the Qimage resample quality? If so, would this work........

First do all print sharpening in Photoshop. That is, over-sharpen.
Then, resample using Qimage,
Then, apply LOW Qimage sharpening (or no Qimage sharpening)

Or is it always best to print sharpen AFTER resampling?
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texshooter

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Re: Printing at 300dpi, 360dpi or what
« Reply #52 on: October 25, 2011, 12:40:48 pm »

Gerald, I'm not surprised that your experiment demonstrated that upsampling/downsampling  to/from  600ppi/300ppi from a starting point of 450ppi gives insignificant improvement. This is likely because our eye does not resolve more  detail beyond 300ppi. That is why your first experiment showed a considerable improvement while your second one didn't.

I'm curious why you didn't test Photoshop's bicubic resampling tool. Are you convinced it is inferior to Lightroom and Qimage for the range of up/down-sampling jobs you typically do?
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Schewe

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Re: Printing at 300dpi, 360dpi or what
« Reply #53 on: October 25, 2011, 03:30:06 pm »

This is likely because our eye does not resolve more  detail beyond 300ppi.

Actually, that's not true...the exact resolution of the eye is based on the viewing distance, not a given PPI. So, if you are viewing an image from 8", a normal person can see about 428PPI. As you move back, the eye can resolve less so at 18" the eye can only resolve 191PPI. This is based upon Bruce Fraser's calculations and the eye's stated resolution of one minute of arc (or 1/60th of a degree). Of course, that's based on high contrast line pairs, a low contrast line pair (more like continuous tone photography) the resolving capability goes down.

So, what resolution you need is based on the final viewing distance...on the other hand, even with big prints photographers tend to walk into an image and look close–Bruce used to say the intended viewing distance of a photographer is limited by the length of his nose :~)

Low resolution is fine for big output that will NEVER bee seen up close but to have a really good output that stands close inspection, you need more resolution.
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