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Author Topic: Clarification on Print Resolution  (Read 142200 times)

Schewe

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Re: Clarification on Print Resolution
« Reply #200 on: June 25, 2011, 03:58:40 pm »

That's interesting, Jeff, I didn't know that.

When I said the output sharpening would be off I meant incorrect (not optimal), not actually turned off.
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John R Smith

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Re: Clarification on Print Resolution
« Reply #201 on: June 25, 2011, 04:07:52 pm »

When I said the output sharpening would be off I meant incorrect (not optimal), not actually turned off.

I see, yes, off as in f*%^-up, rather than switched off.

J
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Mike Guilbault

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Re: Clarification on Print Resolution
« Reply #202 on: June 25, 2011, 11:33:01 pm »

Speaking of output sharpening, is there a definition of "Low, Standard" and "High" sharpening in LR?  Is this something that can be measured or calculated in such a way as to know what setting to use without actually making a test print first?  
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Schewe

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Re: Clarification on Print Resolution
« Reply #203 on: June 26, 2011, 12:55:29 am »

Speaking of output sharpening, is there a definition of "Low, Standard" and "High" sharpening in LR?  Is this something that can be measured or calculated in such a way as to know what setting to use without actually making a test print first?  

Well, JP Caponigro pretty much thought the PK output sharpener over-sharpened while Mac Holbert of Nash editions thought it under-sharpened...so you might say that the the the Low setting was for JP and the High setting was for Mac...in truth the intent was to only provide 1 single setting but Adobe decided to offer 3.

So, if you DON'T optimize the capture settings in Develop, try High (since that tries to overcome under sharpening) and if you tend to over-sharpen in Develop try Low...if you know what you are doing (optimizing the capture sharpening when at 1:) use Standard...And, if you think I'm kidding, I'm really not...that's the way the discussion took place...
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Mike Guilbault

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Re: Clarification on Print Resolution
« Reply #204 on: June 26, 2011, 09:21:03 am »

Well Jeff.. you have a way of putting things that makes sense.  I usually use Low since I hate oversharpening, but I'll try a few at Standard. I've got a pretty good handle on capture sharpening so the Standard may provide better results overall.  Thanks for clearing that up.
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Ernst Dinkla

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Re: Clarification on Print Resolution
« Reply #205 on: June 27, 2011, 06:35:39 am »


I then ran another test to see if altering my capture sharpening could improve things further. As I think you suggested, deconvolution sharpening could result in fewer artefacts, so I went back to the Develop Module and altered my sharpening to Radius 0.6, Detail 100, and Amount 38 (my original settings were Radius 0.9, Detail 35, Amount 55). The next print gained a little more acutance as a result with output sharpening still set to High, with some fine lines on the cup patterns now becoming visible under the loupe. Just for fun, I am going to attach 1200 ppi scans of the prints so you can judge for yourselves, bearing in mind that this is a very tiny section of the finished print.

John

John,

This is not the forum to discuss scanning and sharpening but I am intrigued by some aspects/contradictions of deconvolution sharpening, flatbed scanning and film grain. I have seen a thread on another LL forum  (you were there too) that discussed deconvolution sharpening but little information on flatbed scanners and film grain. I have a suspicion that on flatbeds diffraction plays an important role in loss of sharpness (engineers deliberately using a small stop for several reasons) while at the same time the oversampling as used on most Umax and Epson models keeps (aliased) grain in the scan low and delivers an acceptable dynamic range. In another thread Bart mentioned the use of a slanted edge target on a flatbed to deliver a suitable base for the sharpening. I would be interested in an optimal deconvolation sharpening route for an Epson V700 while still keeping grain/noise at bay. Noise too as I use that scanner also for reflective scans.

The old thread was
http://www.luminous-landscape.com/forum/index.php?topic=45038.0

I could add this reply there too if the thread is still open.


met vriendelijke groeten, Ernst

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/
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John R Smith

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Re: Clarification on Print Resolution
« Reply #206 on: June 27, 2011, 08:07:04 am »

Ernst

I have never done any serious film scanning (I’ve always sent mine out to a lab), so I have no experience of those problems (perhaps it’s just as well).

There is a (possibly insignificant) update from Smith Labs, however, as the latest round of testing reaches a conclusion. No scans today though, I just don’t have time.

* Testing shows that even at a small print size where LR reports a print resolution of 600 ppi, there is a definite gain to be had by resampling in LR to 720 ppi, and there is a visible and worthwhile improvement in fine detail in the print.

* This may be a contentious result, but never mind. My tests seem to show that it is best to avoid print size resolutions with odd numbers like 351, 577 ppi etc. For example, 600 ppi resampled to 720 looks better under a loupe than 601 ppi resampled to 720. Subtle tonal transitions in the original file seem to be rendered more smoothly. However, it may be that my eyesight is just giving up with so much testing and too many late nights  ;)

PS In other words, if you have set up (like I did) for a printed image size of 12x9 ins and the resolution reported by LR is 601 or 603 or 597 or something, resize the cell very slightly to get 600 ppi instead, upsample to 720 and you will get a better print for a fractional difference in printed image size.

If you make use of the User Templates within the Lightroom Print Module, you can get all your favourite print and paper sizes set up with ideal resolutions (in and out) plus your profiles and everything else. It takes a while to sort it all out, but once it’s done you never have to worry about it again.

John
« Last Edit: June 27, 2011, 11:38:19 am by John R Smith »
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Schwarzzeit

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Re: Clarification on Print Resolution
« Reply #207 on: June 28, 2011, 01:51:11 am »

This thread has been a really interesting read.

Are there any limitations in file size for large prints? Would it be possible to send a 64x80" 720 ppi print file to an 11880?
I'm thinking large format scans or stitches where it's possible to have more than 360 ppi detail at this size.

-Dominique

Ernst Dinkla

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Re: Clarification on Print Resolution
« Reply #208 on: June 28, 2011, 03:13:48 am »

This thread has been a really interesting read.

Are there any limitations in file size for large prints? Would it be possible to send a 64x80" 720 ppi print file to an 11880?
I'm thinking large format scans or stitches where it's possible to have more than 360 ppi detail at this size.

-Dominique

Usually that hits on some memory problems. Right now Qimage may handle up to 2 GB image data (64 bits Windows and ample memory) and with the best upsampling + sharpening routines to say 720 PPI at the size you intend the print data becomes huge and that is causing the problems in the end. The easy compromise will be 360 PPI input on the printer. Other routes with RIPs etc may be able to offload more printer data to a 60" printer but their upsampling routines are no improvement. With Qimage there is the Poster Tiles method that splits up the image in more parts, stitched again on the printer so to speak and that can help in this case. It is used for printing longer lengths than the driver allows but has been used to overcome this limitation too. There was another trick for getting image data above the 2 GB limit but I can not recall that. I guess viewing distance is not something that will stop you in adding detail so I did not start with that comment :-)

Edit: to overcome the 2 GB limitation an image could be chopped up in Photoshop and stacked/stitched again by nesting on Qimage's print page and then printed with the Poster Tiles method. That was in a thread some years ago and it never became clear whether that first part ever worked, the Poster Tiles method works for Epsons and Canons though, I have used it.

met vriendelijke groeten, Ernst

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« Last Edit: June 28, 2011, 03:53:35 am by Ernst Dinkla »
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Bart_van_der_Wolf

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Re: Clarification on Print Resolution
« Reply #209 on: June 28, 2011, 04:04:35 am »

This thread has been a really interesting read.

Are there any limitations in file size for large prints? Would it be possible to send a 64x80" 720 ppi print file to an 11880?
I'm thinking large format scans or stitches where it's possible to have more than 360 ppi detail at this size.

Hi Dominique,

Technically there should (!) be no problem sending a 2.7 GP file to the printer driver and spoolfile, assuming they manage memory as they should. However, in 3-channel RGB output that would be almost 8 GB of data, certainly more that e.g. a TIFF file format can store. On a 32-bit OS it will cause problems due to memory management, but on a 64-bit OS it should be 'fine', but there is a chance that drivers or spoolers choke on the amount of data, or the intermediate file size. There are some settings and precautions that can reduce the risk of OS memory problems, as outlined here.

If all the software components play together nicely, it will take a while (=understatement) to print but the resulting image should look very good, and you'll be able to use all the detail that's in the original file when the "Finest Detail" is selected, even up close. Of course you do want to make sure that the heads are well aligned for the medium you are going to use.

Another issue might be, how are you going to mount and transport the beast?

Cheers,
Bart
« Last Edit: June 28, 2011, 09:07:23 am by BartvanderWolf »
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hjulenissen

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Re: Clarification on Print Resolution
« Reply #210 on: June 28, 2011, 02:22:22 pm »

But the highest possible resolution per inch is most relevant for really small prints, where there will be sufficient detail from the camera, and viewers are likely to view it up close, isnt it?

-h
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davidh202

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Re: Clarification on Print Resolution
« Reply #211 on: June 28, 2011, 10:15:28 pm »

Viewing distance in relation to print size is the key to this whole topic.
Roy Lictenstein, and long before him Georges Surat had the answer to pixel peepers.

Stand back and view-   the pixels (dots), blend and dissappear.

http://www.bing.com/images/search?q=georges+seurat&id=D6660BEE75DFE08B586F9F4C6DFBE25AA0D2188E&FORM=IGRE2#x0y0

http://www.bing.com/images/search?q=roy+lichtenstein+images&qs=IM&sk=IM1&pq=roy+lichtenstein+&sp=2&sc=8-17&form=QBIR#x0y4246
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Schewe

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Re: Clarification on Print Resolution
« Reply #212 on: June 28, 2011, 11:00:13 pm »

But the highest possible resolution per inch is most relevant for really small prints, where there will be sufficient detail from the camera, and viewers are likely to view it up close, isnt it?

Well, yes when talking about normal people. the intended viewing distance is considered about 2x the diagonal of the image...but that's for " normal" people...as Bruce Fraser has said, the normal viewing distance for a photographer is only limited by the length of his nose...

Any way you cut it, more is usually better...and if you "can" make something better, why wouldn't you? (and yes, there are times that time prevents you).
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JohnHeerema

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Re: Clarification on Print Resolution
« Reply #213 on: June 28, 2011, 11:36:59 pm »

Quote
Are there any limitations in file size for large prints? Would it be possible to send a 64x80" 720 ppi print file to an 11880?
I'm thinking large format scans or stitches where it's possible to have more than 360 ppi detail at this size.
[/color]

I've encountered some limitations with Lightroom 3, where a file that was 44" x 102" @ 720 ppi simply didn't print (Lightroom produced a blank print from my Epson 9900) - in this case, I downsampled until I reached a resolution where it would print (in my case I eventually downrezed to 180 dpi). Your mileage may vary. For what it's worth, I wasn't memory or disk space limited. This is just one experience though - I haven't taken the time to be scientific about it, so there may have been another factor at work.
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Ernst Dinkla

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Re: Clarification on Print Resolution
« Reply #214 on: June 29, 2011, 03:41:32 am »

Well, yes when talking about normal people. the intended viewing distance is considered about 2x the diagonal of the image...but that's for " normal" people...as Bruce Fraser has said, the normal viewing distance for a photographer is only limited by the length of his nose...

Any way you cut it, more is usually better...and if you "can" make something better, why wouldn't you? (and yes, there are times that time prevents you).

It is like that in the graphic arts too. Detail in a mezzotint, aquatint, washed litho, even the texture of paper and ink in a crude woodblock print, it all counts to give a total impression of a print. It will not be different when landscapes, cityscapes, are displayed on digital picture frames of 10 by 5 feet, you will step closer when detail like a window shows something interesting and when you step back again the picture has changed in your head. Pictures made with wide angles or teles, we never stand at the right nodal point or whatever it is called to get the perspective of the original scene, if the lens perspective ever matches our eyes perspective. Sometimes that is done on purpose, think Bill Brandt. In the end a print is an abstraction of the original scene. Viewing distance is just one factor. Bruce Fraser was right.


met vriendelijke groeten, Ernst

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/
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Schwarzzeit

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Re: Clarification on Print Resolution
« Reply #215 on: June 29, 2011, 04:41:13 am »

Thanks for the input to both of you, Ernst and Bart. I was asking out of sheer curiosity.
So far my largest print has been 56x70" at 304.8 ppi on a Lightjet from a scanned 8x10" color neg. The master file is about 28k x 35k pixels. The downsized print file retained pretty much all the detail. But it's really tight and starts to look digital when some details are reduced to single pixel lines where the the full res file has some room to ramp up the contrast on such lines. There is a natural beauty in oversampling. On the other hand the Lightjet couldn't make use of all the detail of the print file. Some single pixel lines clearly visible on screen, in this case a slight contrast of lighter green lines against a darker green background, didn't make it into the print. It seems the Lightjet needs some threshold contrast at its native pixel resolution. I take it from John's comment about having to reduce the resolution to 180 ppi in order to get all the detail of the file on paper that an inkjet wouldn't be any better when it has to put down high res detail of low to moderate contrast but within similar hue.

Another issue might be, how are you going to mount and transport the beast?
I'm outsourcing my prints. The mounting is done by the lab. There are shippers who can manage the transport of this size.

-Dominique

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Re: Clarification on Print Resolution
« Reply #216 on: July 04, 2011, 07:37:24 pm »

I have read this thread with great intrest! It has been a great learning curve and confirmed a few 'rumours' regarding upsampling etc. Thanks to all who have contributed to this thread!
I do have a question, and if this has been answered, my apologies for asking again.

All this  upsampling etc, seems to based on the final print size then upsampled from there in LR3. That suggests that the end user has control over the orginal image in some form. What if for example, I am given a file that is 8x10 at 360ppi ( from within camera say) but the customer wants it printed to a 16x20? So both the image dimensions and therefore possibly ppi change. Do I change the file dimension in Photoshop leaving the ppi at 360 or resize it and allow the ppi to drop leaving the pixels the same or, from LR set the page to 16x20 and leave the print output at 360ppi? My gut feeling is the later.

Your thoughts would appreciated. 
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JohnHeerema

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Re: Clarification on Print Resolution
« Reply #217 on: July 05, 2011, 02:10:29 am »

Quote
Well, yes when talking about normal people. the intended viewing distance is considered about 2x the diagonal of the image...but that's for " normal" people...as Bruce Fraser has said, the normal viewing distance for a photographer is only limited by the length of his nose...

I've noticed something interesting about viewing distance, which is that when I watch people looking at the prints on my walls, they are surprisingly consistent in how close they come to each of the prints.

That "viewing distance" formula is supposed to include the angular view represented in the print, and in theory at least, is the distance at which the apparent perspective (based on depth cues rather than stereoscopic vision) matches what you would have seen at the point at which the photograph was taken. The theory is that our brains like it when the visual clues we use to gauge distance mesh up when they decode a 2D projection of a 3D scene - which they should do at that calculated viewing distance. Other perspectives are of course used for dramatic effect, but I'm wondering if people naturally tend to stand more or less where the perspective is right.

I've really noticed this on a particularly large print of mine, which is a stitched image where the angular view corresponds to what a very wide angle lens would have recorded. People tend to get quite close to this image. If I look at the image, and imagine being at the scene in question, I find that something clicks when I'm surprisingly close. This matches up with the viewing distance formula (the calculated viewing distance is shorter for wide angles of view, and longer for narrow angular angles of view).

Does this match up with other people's experience? Has anyone else tried observing where people tend to stand when they look at particular prints? Come to think of it, this might be a good time for me to see what's been published on the subject...
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Bart_van_der_Wolf

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Re: Clarification on Print Resolution
« Reply #218 on: July 05, 2011, 03:26:24 am »

I've noticed something interesting about viewing distance, which is that when I watch people looking at the prints on my walls, they are surprisingly consistent in how close they come to each of the prints.

That "viewing distance" formula is supposed to include the angular view represented in the print, and in theory at least, is the distance at which the apparent perspective (based on depth cues rather than stereoscopic vision) matches what you would have seen at the point at which the photograph was taken. The theory is that our brains like it when the visual clues we use to gauge distance mesh up when they decode a 2D projection of a 3D scene - which they should do at that calculated viewing distance. Other perspectives are of course used for dramatic effect, but I'm wondering if people naturally tend to stand more or less where the perspective is right.

Hi John,

The anamorphic projection distortion does have an effect on how we perceive the image, e.g. wide angle effect when viewed from too far or a compressed telephoto effect when we're watching from too close. It also explains why people feel there is something wrong with the 17mm T/S shots of high buildings on a 35mm camera, while they are perfectly undistorted by the lens.

Whether that initial effect is enough to make us adjust the viewing distance, I'm not so sure. In general we want to be able and view a scene as composed by the photographer in 'one view', just scanning the image with our eyes (not by also turning our head). That usually results in a viewing distance that's roughly equivalent to the diagonal dimension of the image.

I think that the main driver for close inspection is curiosity. When we see that there is enough detail to inspect, then we tend to get closer, and see if there is more detail when viewed close up.

If anything, it warrants getting the most out of our prints ...

Cheers,
Bart
« Last Edit: August 12, 2012, 05:57:43 am by BartvanderWolf »
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Ernst Dinkla

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Re: Clarification on Print Resolution
« Reply #219 on: July 05, 2011, 06:39:08 am »

I really wonder whether we fit our viewing position to the original perspective all the time and whether it itches when we can not. I would expect it for larger prints and image content that shows enough depth information and the viewer able to find the right place but with smaller prints it becomes quite impractical, lighting etc blocked by the viewer's presence. In the past photos were generally smaller on whatever image carrier. Larger prints made of telephoto lens images would make it difficult too.  I also wonder how image composition and that natural perspective should relate then. It could become a complex research and considering more abstraction in a B&W print versus color there should be testing done for both categories. Magritte's -Ceci n'est pas une pipe- goes beyond painting.


met vriendelijke groeten, Ernst

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