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Archive 2013 · Uprez before/after processing ???

  
 
RustyBug
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p.1 #1 · p.1 #1 · Uprez before/after processing ???


Is there any advantage / disadavantage to uprezzing a file before starting on the processing vs. uprezzing after finishing the processing (other than more load on CPU) when you know in advance that you'll be printing larger than the file would natively support?


Aug 06, 2013 at 01:16 PM
Bernie
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p.1 #2 · p.1 #2 · Uprez before/after processing ???


Just because I print big, I uprezz most every shot to 24 MPix in ACR from my 12 MP D300.

I then do my PP. From there I then size to the web or print. I am happy using bicubic auto in Photoshop for my 24 x 36" prints.



Aug 06, 2013 at 01:58 PM
RustyBug
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p.1 #3 · p.1 #3 · Uprez before/after processing ???


Thanks,

I usually skip right past ACR into PS, but I do recall the uprezz being possible on the pre-pp side of things, just not part of my typical digital workflow.

I've got one file to prep for about 48-54 inches (long side), coming from a 4500x3000 px file. And a few others that will be around 36-40 inches (long side). Printing this large isn't something I've done before.

I asked if I needed to slightly oversharpen and was told it will be a photographic print (i.e. assumed not inkjet) by the lab and that I can just use PS to uprezz to 250-300 dpi. They'll be printing from jpg/rgb

My thought is that if I uprezz first, then my pp edits will be smoother and more "observable" as I'm working the file ... rather than work the file, do the uprezz and retweak/resharpen after the uprezz algorithm does it's thing. Just wondering if there is something rudimentary flawed that I'm overlooking with regard to large printing (large for me).

Also, is there any diff between uprezzing in ACR vs. in PS?

Edited on Aug 06, 2013 at 02:29 PM · View previous versions



Aug 06, 2013 at 02:23 PM
Peter Figen
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p.1 #4 · p.1 #4 · Uprez before/after processing ???


The biggest advantage of uprezzing first is that any retouching you do will be at the new file size. You'll be surprised at how sloppy you can be when you enlarge you retouching two hundred percent. You do want to be really careful about any sharpening applied at the raw processing stage or in Ps before the interpolation. Halos look great on angels but not so much on large prints. And, of course, the disadvantage is file size.

I just finished working on a huge retouching job for the Los Angeles MTA, and one of the files was so large high res by the time I built the basic base file with layers that I duped that and then downsized it. The psb file was still over eleven gigs and the final 8 bit CMYK came in at about a gig and a half, zipped.




Aug 06, 2013 at 02:29 PM
RustyBug
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p.1 #5 · p.1 #5 · Uprez before/after processing ???


Peter Figen wrote:
The biggest advantage of uprezzing first is that any retouching you do will be at the new file size. You'll be surprised at how sloppy you can be when you enlarge you retouching two hundred percent.


This ^ is what I was thinking.

You do want to be really careful about any sharpening applied at the raw processing stage or in Ps before the interpolation. Halos look great on angels but not so much on large prints..

I usually have sharpening set to 0 as I pass through ACR, doing all my sharpening in PS instead.

And, of course, the disadvantage is file size.

Only five files for this project, so even if it goes a bit slower, I can probably tolerate it ... although it might cost me an extra or two along the way.

I just finished working on a huge retouching job for the Los Angeles MTA, and one of the files was so large high res by the time I built the basic base file with layers that I duped that and then downsized it. The psb file was still over eleven gigs and the final 8 bit CMYK came in at about a gig and a half, zipped.

I don't think I'll be anywhere remotely near that size.
Do you find that over-rez, pp, then downsize has merit as a routine practice ... or should I just uprezz for target output size and leave it at that?

BTW, if you guys are uprezzing first, then I feel pretty secure about going that route. Thanks again, that removes the doubt that I may have overlooked something significant.



Aug 06, 2013 at 02:36 PM
Peter Figen
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p.1 #6 · p.1 #6 · Uprez before/after processing ???


There's no real advantage to over-rez and then downsample unless you're hyper paranoid about really finely detailed retouching, but even then, it's not something I ever do.

I have done some comparisons between upsampling with sharpening vs. the same without, and surprisingly enough, I can see a tick more detail when I do a very mild pre-res sharpening. May or may not matter to you, but something to think about.



Aug 06, 2013 at 06:34 PM
RustyBug
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p.1 #7 · p.1 #7 · Uprez before/after processing ???


Gotcha @ up/down vs. paranoid. I did some testing on it a year or so ago and didn't see much diff, but just thought I'd ask just in case.

Hmmm, not sure why pre-upres sharp would do that ... may run a test or two. I can be a bit "retentive" since I do mostly "one-off" stuff. Recommendation @ pre-upres sharp, i.e. HIRALOAM or

BTW ... I'm really diggin' your mode @ darken/lighten for opacity @ "one way" sharpening. I'm finding that I can oversharpen to visual perception, then pull back to about 80% on darken and 30% on lighten layers gives me a nice way to control halos in certain situations that I had been having trouble with. Thanks again.



Aug 06, 2013 at 06:47 PM
Hammy
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p.1 #8 · p.1 #8 · Uprez before/after processing ???


I think everybody's situation would be different - like do you do one print a week or serveral thousand per week like we do.

To me, uprezzing before PP means that every other process that I apply to the image will take more time and more memory.
Another issue would be alternate destination sizes. Uprezzing to AAAAxBBB, then realizing that I need/want CCCCxDDD resulted in all that extra effort (for my PC) and extra time for naught.
But doing all PP with native import image, things happen fast, then the last thing to do is resize.

Again, that it in line with my workflow. I could see benefits of working on a large file to get USM or other artifacts out of the way so unexpected issues don't show up.



Aug 06, 2013 at 09:25 PM
Mr Joe
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p.1 #9 · p.1 #9 · Uprez before/after processing ???


Jeff Schewe recommends leaving the resolution as is for big prints if the file is natively 180 ppi or higher. Upressing in the RAW converter has worked well for me when necessary. I highly recommend using a small amount of capture sharpening in the RAW processing phase.


Aug 07, 2013 at 09:35 AM
ben egbert
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p.1 #10 · p.1 #10 · Uprez before/after processing ???


Mr Joe wrote:
Jeff Schewe recommends leaving the resolution as is for big prints if the file is natively 180 ppi or higher. Upressing in the RAW converter has worked well for me when necessary. I highly recommend using a small amount of capture sharpening in the RAW processing phase.


This is the way I do it, and I have read Jeff and others on the matter. I use Qimage however and just let it do the final uprez and output sharpening (4). I print as high as 29 inches wide on files with 5760 pixels that 198 ppi.

I use settings of 50,0.6,7 and mask 30 in ACR. This is almost sharp enough, but I sometimes do a bit of final sharpening for haze and a light USM at the end.

I never uprez other than what Qimage does. I never print from Photoshop, not smart enough to memorize all the settings you have to go through.




Aug 07, 2013 at 09:51 AM
RustyBug
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p.1 #11 · p.1 #11 · Uprez before/after processing ???


Thanks guys.

I took a quick re-read @ Uwe Steinmuiller's Fine Art Printing, but it is largely targeted toward inkjet (which this will likely not be). I'll revisit Jeff's sharpening book too, to see what I might glean from it.

Small amount of capture sharpening =

The lab is asking for 300 dpi, but is okay with 250+ which would be 12,500 @ 250 x 50 inches. Coming from 4,500. I'll probably go to an "even" 300% @ 13,500 which would be 270 @ 50 inches. 200% @ 9,000 would only be 180, 250% @ 11,250 would be 225.

That should be the longest/largest uprezz I need to make.

Edited on Aug 08, 2013 at 10:36 AM · View previous versions



Aug 07, 2013 at 10:15 AM
Peter Figen
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p.1 #12 · p.1 #12 · Uprez before/after processing ???


What type of print are you making? How is it being displayed? What is the average viewing distance, factoring out people who might put their reading glasses on for a closer look. Even though the lab is asking for 300 dpi, they always ask for that no matter the context. So many factors influence this including the front end of the printer they're using.


Aug 07, 2013 at 11:54 AM
RustyBug
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p.1 #13 · p.1 #13 · Uprez before/after processing ???


+1 @ the variables.

Viewing distance is mixed as they will be seen from 6-8 feet as people are passing by the hostess station en route to seating, while those traveling the hallway will be arms' length and those seated with viewing angle will be around 8-15 feet. I don't see any real "pixel peeping" going on in this environment (not enough to give a hoot, anyway).

I just spoke with customer service @ lab ... they are using Fuji Crystal Archive Luster (per the client's request/preference). The printer is Noritsu. The model unknown atm, icc profile and additional printer info being forward to me once CS finds out more info. I asked @ front end, but they were atm.



Aug 07, 2013 at 12:24 PM
RustyBug
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p.1 #14 · p.1 #14 · Uprez before/after processing ???


Revisited Jeff Schewe/Bruce Fraser @ 2nd Edition Real World Image Sharpening.

Reference to human visual acuity & viewing distance (table @ pg 77) suggests the following relationship, following the formula of L = D*TAN(0.00029089) where L= limit of visual acuity (20/20 assumed) at Distance D. From that, 1/L=dpi

The basis for this is given as the threshold of normal (20/20) visual acuity is one minute of arc (1/60 of one degree) = 0.00029089 radians.

Viewing Distance (Inches) : Resolution (dpi)

12 : 286
15 : 229
18 : 191
20 : 172
24 : 143

I find it interesting that the 300 DPI has a seemingly universal regard as the "must have" by so many. Yet, plugging in a viewing distance of 48" into the formula, we get:

48 : 72

I've not done the trig for those with better than 20/20, i.e. 20/15 (limits of natural vision) or 20/10 (limits of corrected/aided vision), but from a viewing distance of 48 inches that works out to 72 dpi for 20/20. While trig functions are nonlinear (to adjust for differing visual acuity), the concept that one would need a 4X factor (to yield near 300 dpi) for a viewing distance of 4 feet does now seem a bit overkill, even for those with better than 20/20 vision. Personally, I'm at 20/15 (corrected/aided), so I've often felt like many "large prints" were too soft, but at least I can better understand that relationship now.

Given that, even at arm's length, the minimum viewing distance of 15"-18" puts it in the 230-190 range. Not until we are at 12" do we approach 300 dpi (286). Kind of hard to view a 36" - 50" print (in it's entirety) from only a 12" viewing distance. So the need to achieve 300 dpi now seems a bit moot as a "hard" requirement for such a large print. This I would contrast/compare to the viewing distance that the lab (or we) might be using for inspecting the print (QA/QC). Here 12" viewing distance would seem more appropriate for viewing the print in sections looking for problem areas, rather than viewing as a whole.

Now it makes a bit more sense to me why some folks advocate 300 dpi as "universal" and others (well regarded) suggest that over 180 dpi and your good. I've never really believed that "dive bomb 300" was the right answer, but I admit I didn't know what the right answer really should be. This has been a good exercise for me, with the salient point for me being the (self made) distinction between the differing rationale for viewing a print vs. inspecting a print. Handling an 5" x 7" print that can be viewed in it's entirety from a viewing distance of 12" ... 300 dpi seems pertinent ... for a 30" x 40" inch print, hmmm @ not so much.

So, is it necessary to uprezz to 300% to achieve near 300 dpi ... maybe not.

BTW, I took another re-read through everyone's posts. Things are a bit more clear to me now ... thanks to all.






Aug 08, 2013 at 09:56 AM
Eyeball
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p.1 #15 · p.1 #15 · Uprez before/after processing ???


I think the type of image can influence the PPI requirements. Sometimes you want an image to be enjoyed at multiple distances and it can be kind of cool when an image reveals additional details as you approach the print. In those cases, you probably want to push the PPI as much as you can.


Aug 08, 2013 at 11:57 AM
RustyBug
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p.1 #16 · p.1 #16 · Uprez before/after processing ???


Thanks Dennis, I was kinda of leaning that way for one image in particular. Good to hear that it is reasonable for consideration.

I'm beginning to realize that this isn't as much an absolute "do this, do that" as it is an "it depends".



Aug 08, 2013 at 12:05 PM
Peter Figen
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p.1 #17 · p.1 #17 · Uprez before/after processing ???


"I find it interesting that the 300 DPI has a seemingly universal regard as the "must have" by so many."

Three hundred dpi came from offset lithography and just sort of stuck. A line screen of 150 generally wanted 300 dpi to be safe in terms of stairstepping. In reality, you could usually get by with 200-225 for a 150 l/s and never see a problem - usually...

All of those recommended viewing distance/resolution charts assume you have actual resolvable detail to see, and when you're rezzing your files up, you're not adding any detail, but often are avoiding other artifacts, so take those all with a grain. I've scrutinized plenty of large prints at a foot or less that were printed at 150-180 dpi on an Epson 9900. Never felt a lack a detail. In fact, you'd be hard pressed to pick out the 180 dpi print from a 360.

All in all, people worry way too much about the resolution and far too little about the content.



Aug 08, 2013 at 12:21 PM
RustyBug
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p.1 #18 · p.1 #18 · Uprez before/after processing ???


Peter Figen wrote:
All in all, people worry way too much about the resolution and far too little about the content.


Imo, that's largely because we get get beat to death by it (300 dpi). Those who have little experience (self included obviously) with significant printing are left to trying to find good guidance from others. Whether it comes from a book written by well regarded individuals, or from talking with professional lab technicians, or seasoned photographers from around the world ... likely nothing will replace the experience of doing it.

It doesn't help when you are hours away from the nearest real lab, and if they are also advocating 300 dpi ... well, it's no wonder that ignorant (not to be confused with dumb)/inexperienced printing efforts are so fraught with the obsession toward resolution. It's incessantly preached and except for finding folks that are willing to share their knowledgeable voice of experience, it is difficult for a person inexperienced with printing to discern fact, fiction, myth and popular misconception from one another.

Back in the day, it was too easy for me. I shot Fujichrome 50 for its very fine grain structure. When I needed a print, I'd give it to the lab and that's all there was to it. Now, that we're in digital, we've got a plethora of variables (careful what you ask for, you just might get it) at our disposal/control.

Peter Figen wrote:
All in all, people worry way too much about the resolution and far too little about the content.


Well, up to this point I've worried mostly about content, so this makes me feel like I've put my priorities in reasonable order. Of course, the client made their decisions based on content, not the resolution. I just want to be sure to give them the best that I can toward what they deserve. While not my first client ... it is my first "large print" client, so I'd like to get it as close to right as I can for a "large print" (yeah, still kinda small compared to some of you guys) rookie.

I've tried to heed my own advice @ "ask the lab", i.e. trust the voice of professional experience. Funny though, in much regard I've come to trust the voice of experience from seasoned FM'ers more than my nearest lab.

Anyway ... I've pretty much abandoned the notion of a 300 dpi target. I'll likely have them ranging between 200-250 depending on what size the client/framer finally decide on. Of course the real tale of the tape will come once they're hung, but I'm feeling reasonably good (much thanks to cross-checks with fellow FM'ers) that I won't be embarrassed to see them on the client's wall just because I didn't hit the "magic" 300 dpi.

For ref, the content can be seen here: https://www.fredmiranda.com/forum/topic/1230705
These were my "draft concept" small jpgs, not the final PP from raw, so don't put too much stock in them as a finished product (more like a proof), but C&C is always welcome.

Thanks again to all. I'll meet with framer/studio today to make final crop/size decision, and then the files are off to the lab.



Aug 09, 2013 at 04:59 AM
Mr Mouse
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p.1 #19 · p.1 #19 · Uprez before/after processing ???


Every time you interpolate an image you loose some image quality. The simple fact is the best pixels you have for you image are the ones you get straight from your camera. The quality of these pixels may not be the best for they are the results of many factors. Like exposure, ISO, Quality of your lens, Your Camera sensor and firmware etc. However they are the pixels you managed to capture using a device design to capture pixels for an images. Not pixels generated by some computer algorithm interpolating a different pixel size image. Interpolation either troughs away detail you have for and image or invent detail you don't have for an image.

There are only two reasons I see for interpolating an image.

One you need an image that has fewer pixels so it will display and fit on a device that does not have the number of pixels your image has or is going to be used in media that require images to fit within some pixel size like a area in a web page.

The other reason to interpolate is when you have too few pixels. Like the results of a crop left you with few pixels and little detail. You can try to interpolate the image up in pixel size to see if the interpolated pixels will produce a better looking print or you may be able to modify the interpolated added pixels to improve to their appearance.



Aug 10, 2013 at 07:47 AM
RustyBug
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p.1 #20 · p.1 #20 · Uprez before/after processing ???


+1 @ original vs. interpolated -detail/invent "detail"/modify interpolated pixels.

I got a chance to discuss with the studio about their lab as they reviewed my files. He said that these are going to be printed on a Fuji Frontier. Oddly enough, as we were discussing the resolution and the lab's requirements, he said that from his years of working with the lab (not the CS) they prefer to have 15" @ 300 dpi (referring to native file) rather than an interpolated 30" @ 300 dpi that has been interpolated because of how their printer will interpret/uprezz differently than PS.

Okay, well after three calls to the lab to discuss how they want the file prepped ... and getting the same uprezz in PS to 300 dpi answer, this came as a bit of a surprise. Judging from his prints in his studio, his work speaks for itself. Of course, that left me scratching my head as to why I went through all the effort to uprezz and resharpen for the larger print when I was already at 4500 (15" @ 300 dpi). I feel like I prepped my files well with a different sharpening algorithm to go along with viewing distances, but still ... really

Well, if the lab really prefers the native file and let the printer do it's thing, why did't the lab CS just say that, instead of telling people that you should be at 300 dpi and they need to uprezz to 300 dpi in PS first. Aaaargh

On an anecdotal note,I had one solicitation for some competition/donated work (few years back) ask for files @ 300 dpi. When I responded by asking them at what size would they be printing they said they didn't know, but just submit the files @ 300 dpi. I didn't bother.

So, which is it ...

A) Send native and let the printer algorithm figure it out
B) Uprezz/size to viewing distance dpi
C) Uprezz/size to 300 dpi

D) If native >= viewing distance, send native
E) If native < viewing distance, uprezz to viewing distance
F) If native < viewing distance, uprezz to 300 dpi

G) It doesn't really matter, anyway. People will be viewing from so many different distances that it will always be wrong at some distance.
H) It doesn't really matter, anyway. The diff @ 180 dpi -300 dpi is indiscernible to 99% of the world, no matter how many people say 300 dpi is a must.
I) It doesn't really matter, anyway. Who gives a rat's behind, it's only a picture.

J) Ask the Ouija board

Why does something that should seemingly be so simple and straightforward, be so convoluted with a different answer every time you turn the corner? Is there a "right answer or is it always going to be depends on who you ask? And we wonder why the general public is "misinformed".









Aug 10, 2013 at 09:06 AM
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