Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-27-2010, 08:36 AM   #1
Inactive Account




Join Date: Dec 2008
Location: Texas
Posts: 51
Image Size vs Document Size vs Resolution vs Resampling vs ... AHHHH!

My apologies ... I'm sure this poor horse has been beaten to death by now, but I couldn't find the exact answers via searching the forum. Please help salvage my sanity ...

Note: all images shot with K20D at optimal quality - some JPEG, some RAW
  • I'm having these printed by Mpix
  • I need my printed images to be 16x24"
  • The "print size" of my images defaults to between 10x15" and 43x64" - depending on the image file size - in PS CS3
  • The Document Size / Resolution (in Image Size utility) defaults to 72
  • I've always heard printing at 300 PPI is optimal, so I changed the 72 to 300
  • And, as expected, the Document Size adjusts itself accordingly, to 10x15"
  • But I want 16x24"
  • So I check the "Resample Image" box, which maintains the 300 PPI when I reenter 16x24" as my document size.

So what the heck will my prints from Mpix look like after I've modified & resampled to 300PPI and 16x24"?? If this is wrong, what should the settings be?

I confess ... I'm printing inept. This phase of photography is my weak area. I don't know what to change when and what to change them to. I've got a good book on order, but until then, I could use some Pentaxian wisdom here so I don't waste $ on these prints due to my incorrect settings. Help?

07-27-2010, 08:52 AM   #2
Ira
Inactive Account




Join Date: Mar 2009
Location: Coral Springs, FL
Photos: Gallery | Albums
Posts: 5,216
You did everything right and seem to understand the concept. But it all depends on how the piece is being printed, their equipment and software.

It might have not been necessary to resample, like 200 might have been enough. I say this because I'm using an old version of Photoshop, and I can't really resample more than 15% without noticing a degradation.

If you're having it printed on the outside, it's just something you're going to have to experiment with. Like, even now, if you could afford to, it would be cool to print both resolutions (resampled and not) and see whether you needed to resample, and if quality is actually DEGRADED because of it.
07-27-2010, 08:53 AM   #3
graphicgr8s
Guest




QuoteOriginally posted by veezchick Quote
My apologies ... I'm sure this poor horse has been beaten to death by now, but I couldn't find the exact answers via searching the forum. Please help salvage my sanity ...

Note: all images shot with K20D at optimal quality - some JPEG, some RAW
  • I'm having these printed by Mpix
  • I need my printed images to be 16x24"
  • The "print size" of my images defaults to between 10x15" and 43x64" - depending on the image file size - in PS CS3
  • The Document Size / Resolution (in Image Size utility) defaults to 72
  • I've always heard printing at 300 PPI is optimal, so I changed the 72 to 300
  • And, as expected, the Document Size adjusts itself accordingly, to 10x15"
  • But I want 16x24"
  • So I check the "Resample Image" box, which maintains the 300 PPI when I reenter 16x24" as my document size.

So what the heck will my prints from Mpix look like after I've modified & resampled to 300PPI and 16x24"?? If this is wrong, what should the settings be?

I confess ... I'm printing inept. This phase of photography is my weak area. I don't know what to change when and what to change them to. I've got a good book on order, but until then, I could use some Pentaxian wisdom here so I don't waste $ on these prints due to my incorrect settings. Help?
CS3 does a decent job at resampling. They changed the algorithms from CS2 and it works better. I've gotten excellent results printing 16 x 20 at 200 dpi. I won't tell you how low I've gone and still had acceptable output.
07-27-2010, 09:02 AM   #4
Ira
Inactive Account




Join Date: Mar 2009
Location: Coral Springs, FL
Photos: Gallery | Albums
Posts: 5,216
QuoteOriginally posted by graphicgr8s Quote
CS3 does a decent job at resampling. They changed the algorithms from CS2 and it works better. I've gotten excellent results printing 16 x 20 at 200 dpi. I won't tell you how low I've gone and still had acceptable output.
I remember that you told me that. Just wish I could afford it one day.

07-27-2010, 10:25 AM   #5
Senior Member
landscaped1's Avatar

Join Date: Jan 2010
Location: Louisiana
Photos: Gallery
Posts: 153
veezchick - The way I go about it that really seems to simplify the process. Decide the print size and the desired resolution (personally between 150-300) and just use the crop tool. when you select the crop tool, on the top tool bar there is a place where you can enter the desired crop size (width and Height) and also a box for resolution. This will take care of the process all in one easy step!
07-27-2010, 11:12 AM   #6
Pentaxian
JohnBee's Avatar

Join Date: Sep 2008
Location: front of computer
Posts: 4,630
QuoteOriginally posted by veezchick Quote
I confess ... I'm printing inept. This phase of photography is my weak area. I don't know what to change when and what to change them to. I've got a good book on order, but until then, I could use some Pentaxian wisdom here so I don't waste $ on these prints due to my incorrect settings. Help?
IMO. The first and most important thing to know is that resolution ex: 1024px X 768px, are always the determining factor in digital images. Therefore... all other attributes are either secondary or a subset of that value.

Therefor when you prepare an image for print by adjusting the output size and DPI parameters, Photoshop will optimize the output by re-sampling the image(smaller or larger).

With this in mind, the proper procedure would be:

1. Adjust your Document Output Size(Inches)
2. Adjust your Target Resolution(PPI)

Photoshop will make the necessary adjustments(re-sampling etc) to optimize output.
Obviously, you can override this and take control of settings yourself(should you want too). However Photoshop is pretty good at averaging the settings for most printers.

Obviously, there is much MUCH more to talk about with reference to digital imagery and print. Not to mention the abyss of confusion that lies between the user and the media(don't even get me started on that). But the good news is, that we don't have to concern ourselves with this at this stage of things. Photoshop does a good job of calculating averaging things and providing us with good prints on most all printers.
07-27-2010, 02:23 PM   #7
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by veezchick Quote
Note: all images shot with K20D at optimal quality - some JPEG, some RAW
Assuming these aren't crops, that means you've got 3104x4672 pixels.

QuoteQuote:
[*]I need my printed images to be 16x24"
So just ask Mpix to do that. You don't need to mess with anything at all in the file to make that happe. Mpix is perfectly capable of creating a 16x24" print whether or not you fiddle with the file first. In particular, you *definitely* needn't be concerned with what Photoshop says the size would be if you happened to print at the default of 72ppi.

QuoteQuote:
[*]I've always heard printing at 300 PPI is optimal, so I changed the 72 to 300
That doesn't affect a thing except the canvas size as displayed by Photoshop. Your image still has 3104x4672 pixels, so the actual print resolution won't have changed a bit. Unless you do something to decrease or increase the number of pixels, that means a 16x24" print is 3104/16 = 4672/24 = 194dpi.

While you can certainly ask Photoshop to make up pixels for you to bring the total up to the necessary 16*300 x 24*300 = 4800x7200 you'd need to get to get a 300dpi print at 16x14", it's not really necessary. Made up pixels are made up pixels; you're not *really* getting any higher resolution. And that's fine - at that size, 194dpi is more than good enough. You don't normally view a 16x24" print from anywhere near as close as you would a 4x6 or even 8x10".

Of course, the printer itself *always* prints 300ppi - that's all it is physically capable of doing. So one way or another, someone is going to be making up those extra pixels to get to 4800x7200. The only question here is whether you do yourself in Photoshop (by selecting one of the resizing / rescaling options), whether you let the folks at Mpix do it (also most likely in Photohop), or whether the folks at Mpix just let the printer driver do it automatically.

Of these three options, I think the first is *least* likely to produce optimal results, unless you really know what you are doing and how to optimally control the rescaling process. I'd expect the folks at Mpix or the folks who designed the printer driver for the printer they use to know *far* more about the process than you (or I, or pretty much anyone not in the printing business). So my recommendation would be to not mess with any of this - just give them the file right as it comes out of the camera or as edited within Photoshop but with no attempt on your part to make up pixels yourself (eg, don't try to resize / resample, and again, no need to mess with the resolution figure).

QuoteQuote:
[*]So I check the "Resample Image" box, which maintains the 300 PPI when I reenter 16x24" as my document size.
For the record, this is indeed how you tell Photoshop to make up enough extra pixels to give you 4800x7200, which is what you need for 300ppi at 16x24". But there may be different options for selecting the specific resampling (= pixel making-up) algorithm used, and different algorithms work better for different images. Which is part of why I say you're not likely to be better off by messing with this. But I'd assume the default resampling algorithm wouldn't be noticeably worse than if Mpix just let the printer driver handle the resampling. So unless Mpix does custom processing, it probably won't hurt to do what you're doing here. It basically works out to a big no-op, though (meaning, a bunch of steps performed with no real effect. Again, just handing them the file straight from the camera would print at exactly the same resolution.

And, BTW, you're right - there have been many existing threads on print resolution. You're not even close to the first person to be confused by all this. But it's really quite simle if you keep in mind that in the end, it all comes down to how many pixels you have and how many inches you print. If you have X pixels and print at Y inches, the resolution is X/Y.
07-27-2010, 04:41 PM   #8
Ira
Inactive Account




Join Date: Mar 2009
Location: Coral Springs, FL
Photos: Gallery | Albums
Posts: 5,216
QuoteOriginally posted by JohnBee Quote

With this in mind, the proper procedure would be:

1. Adjust your Document Output Size(Inches)
2. Adjust your Target Resolution(PPI)

Photoshop will make the necessary adjustments(re-sampling etc) to optimize output.
Photoshop can only do so much:

You can't expect it to take an 8 by 10 file at 72dpi and make that file usable for anything bigger than printing at like 2 by 2.5 inches.

07-28-2010, 08:36 AM   #9
Veteran Member
lurchlarson's Avatar

Join Date: Nov 2008
Location: Oregon, USA
Photos: Albums
Posts: 683
Doesn't Mpix do the resampling for you?
07-28-2010, 10:03 AM   #10
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Yes, mpix will resample for you, as do all other major print services. The question would be, is upscaling is needed, could you perhaps do a better job of it on your own if you have appropriately sophisticated software and the necessary knowledge and experience to make effective use of it. For some, the answer will be yes, but most are best off letting the pros do it.
07-31-2010, 06:39 PM   #11
Veteran Member
khardur's Avatar

Join Date: Feb 2007
Location: NW Massachusetts
Photos: Gallery
Posts: 1,506
the ppi vs. print size vs. actual pixel dimensions was covered pretty nicely...

I've done a ton of prints from 8x10's up to 20x30's and only for one photo did I ever resample the image to enlarge to the proper dimensions. I even cropped out an 8x10 portion and ordered a test print to see if it was going to have any issues... (no it didn't)

But in 99.9% of the other cases I just send the file @ the original dimensions to the printer. Often times they even have a slider or meter next to your picture that shows you the quality level of the file you supplied for the size/crop you are doing.

I would forget resampling, especially for 16x20. There are plugins that can resize with negligible loss of quality (something with fractal in the name, but I can't remember) - but I'd say that really would only be necessary if you planned on doing a huge print from a file that was very teeny in pixels.

Speaking of which - that may be a neat idea sometime - intentionally reduce an image so much to get it to pixelate. (I mean huge pixels) Dang now you've got me thinking...
07-31-2010, 08:28 PM   #12
Senior Member




Join Date: Mar 2010
Location: VA
Photos: Albums
Posts: 227
QuoteOriginally posted by khardur Quote
Speaking of which - that may be a neat idea sometime - intentionally reduce an image so much to get it to pixelate. (I mean huge pixels) Dang now you've got me thinking...
Try upscaling using bilinear to exaggerate the pixels.
08-02-2010, 01:11 PM   #13
Inactive Account




Join Date: Dec 2008
Location: Texas
Posts: 51
Original Poster
QuoteOriginally posted by veezchick Quote
So I check the "Resample Image" box, which maintains the 300 PPI when I reenter 16x24" as my document size.
Thanks so much for the feedback and great info everyone. I let the above settings ride and the prints came back beautiful. The next time, I'll keep them straight for comparison. Thanks again.
08-02-2010, 03:57 PM   #14
Ira
Inactive Account




Join Date: Mar 2009
Location: Coral Springs, FL
Photos: Gallery | Albums
Posts: 5,216
Glad it worked out!

Things are very different nowadays for print output than they used to be. The parameters and file preps were much stricter.

For example, your image is RGB now, yet the printer has to do a conversion and spit out CMYK inks onto the paper. So what's up with THAT!? Yet it does it.

Same thing with resolution:

As long as the pixels are there, most print drivers, RIP (Raster Image Processing) programs, and even layout programs like InDesign where you place an image as a placeholder don't nee the correct image size at a certain resolution. As long as the pixels are there, they do the calculations and make it work.

HOWEVER................

Image size and resolution are important for files that are actually going to an offset press, where it's "screened." So if you're ever going to send a job for actual printing on a press, post again.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
document, image, images, photography, photoshop, size, vs
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Image size Jacos Troubleshooting and Beginner Help 15 04-11-2010 02:47 PM
JPEG Image Size hcc Troubleshooting and Beginner Help 21 04-10-2010 08:44 PM
Size/resolution Bramela Digital Processing, Software, and Printing 7 09-04-2009 09:30 PM
New monitor resolution wrong size Artesian Photographic Technique 11 02-11-2008 09:44 PM
New Sony APS-C size CMOS Image Sensor with 12.47 Effective Resolution for use in DSLR Matjazz Pentax DSLR Discussion 4 08-20-2007 02:42 PM



All times are GMT -7. The time now is 12:48 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top