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How do I get "clear" images when printing a 16x24 of a hi-res .jpg
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Dec 23, 2013 09:07:59   #
TheDman
 
f8lee wrote:
See, here s where you make a mis-step. That article (lovely by the way) speaks to the concept of SCANNING at 72DPI as some magical myth, which it is. This is not the conversation being had here.


No misstep. You obviously didn't read past the first sentence. But here's a few more links that all agree with me too that don't say anything about scanning:
http://www.webdesignerdepot.com/2010/02/the-myth-of-dpi/
http://www.photoshopessentials.com/essentials/the-72-ppi-web-resolution-myth/
http://www.rideau-info.com/photos/mythdpi.html

I could find dozens more too.



f8lee wrote:
I specifically stated that an image saved as a 4x6 at 300 DPI will just be excessively large if it is to be only displayed on a screen. Even if modern monitors are denser than 72PPI, there is still no need to save an image that will be 1200 pixels by 1800 pixels (or to be more drastic, say a 16x20 image at 300 DPI meaning 4800 x 6000 pixels)



What? Why does 300 DPI mean 4800 x 6000? That doesn't even make any sense. It's the same as saying if you're driving 65mph in your car then you must be going 1000 miles.

Any size image can be any dpi. A 4800x6000 image can be 1 DPI. A 10x10 image can be 300 DPI. And if you saved a 10x10 image at 1 DPI and 300 DPI, the file size would be exactly the same, and would take the same amount of time to download.

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Dec 23, 2013 09:12:44   #
TheDman
 
beauxPatrick wrote:

I am still confused as to the relationship between something large at 72dpi reduced to 16x24 at 288 or 300???


There is no relationship. Just set your DPI to whatever your printer's optimal resolution may be.

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Dec 23, 2013 09:18:51   #
f8lee (a regular here)
 
TheDman wrote:
What? Why does 300 DPI mean 4800 x 6000? That doesn't even make any sense. It's the same as saying if you're driving 65mph in your car then you must be going 1000 miles.

Any size image can be any dpi. A 4800x6000 image can be 1 DPI. A 10x10 image can be 300 DPI. And if you saved a 10x10 image at 1 DPI and 300 DPI, the file size would be exactly the same, and would take the same amount of time to download.


Which is why, once again, i specifically stated a 16x20 inch image at 300DPI. Multiple 16 by 300 and guess what - that's 4800 pixels.

Image files are tagged with the display size (in a rough manner) - "pixel peepers" are those who prefer to view the image at the individual pixel level; for them the 4800 pixels width of my example image would fall off the ends of the screen if the screen in question is a typical 1280 x 800 pixel screen.

As you imply, pixels are pixels; how many of them appear per inch depends on what they are appearing on. For printers that run at 300DPI, files saved at that resolution make sense. If you view that same file on a monitor, the monitor driver ignores many or most of the actual pixel data in the file.

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Dec 23, 2013 09:21:02   #
krakkaz
 
Ha, happy looking dogs. I would just try using a faster shutter speed and a little more light.

Like boberic said, it's not about how anyone likes the shots but the customer.

Good work in my opinion.

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Dec 23, 2013 10:00:35   #
Morning Star
 
f8lee wrote:
I specifically stated that an image saved as a 4x6 at 300 DPI will just be excessively large if it is to be only displayed on a screen. Even if modern monitors are denser than 72PPI, there is still no need to save an image that will be 1200 pixels by 1800 pixels (or to be more drastic, say a 16x20 image at 300 DPI meaning 4800 x 6000 pixels)


TheDman wrote:
What? Why does 300 DPI mean 4800 x 6000? That doesn't even make any sense. It's the same as saying if you're driving 65mph in your car then you must be going 1000 miles.


It DOES make sense if you take all three parts of the equation: dimension in inches x pixels (not dots) per inch = dimension in pixels.
Or, to paraphrase f8lee: 16 x 20 (inches) image at 300 ppi (NOT dpi) = 4800 x 6000 pixels.

In your car example you give only two parts of the equation: speed and total distance, but you left out the time it took (15 hrs, almost 23 minutes). So, to paraphrase that: 1000 mile trip at 65 mph = 15 hrs 23 min.

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Dec 23, 2013 11:26:09   #
TheDman
 
f8lee wrote:
As you imply, pixels are pixels; how many of them appear per inch depends on what they are appearing on. For printers that run at 300DPI, files saved at that resolution make sense. If you view that same file on a monitor, the monitor driver ignores many or most of the actual pixel data in the file.


The monitor doesn't ignore anything. It displays every one of the pixels in the image. There are no hidden pixels that you can't see on a monitor that the printer does see.

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Dec 23, 2013 12:57:39   #
f8lee (a regular here)
 
TheDman wrote:
The monitor doesn't ignore anything. It displays every one of the pixels in the image. There are no hidden pixels that you can't see on a monitor that the printer does see.


Okay - last attempt here.

Get yourself a large image - say, 4096 pixels across, or even larger. Save it in Photoshop as being 2 inches across, giving it a 2448 "resolution".

View it on the screen. How large is it on that screen? How many pixels does your screen physically have? If it's a QXSGA it's about 2000 pixels across. That's the physical pixel count of the physical monitor. Got it?

Now when you view that image on your screen, does it require you to scroll all the way to the right to see the other half? Or does it pretty much show the entire image without scrolling? If you have a VGA monitor, what then?

Again, you saved a file with over 4000 pixels and it displays on your monitor that has decidedly less than 4000 pixels. Where do you suppose all those extra pixels go?

Feel free to debate further - I give up trying to explain beyond this.

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Dec 23, 2013 13:29:59   #
TheDman
 
f8lee wrote:
Okay - last attempt here.

Get yourself a large image - say, 4096 pixels across, or even larger. Save it in Photoshop as being 2 inches across, giving it a 2448 "resolution".

View it on the screen. How large is it on that screen?


4096 pixels across.


f8lee wrote:
How many pixels does your screen physically have?


Mine is 2560x1440. And it has scroll bars.


f8lee wrote:

Again, you saved a file with over 4000 pixels and it displays on your monitor that has decidedly less than 4000 pixels. Where do you suppose all those extra pixels go?


On the sides, for me to view when I scroll. ALL of them. It does not "ignore many or most of the actual pixel data in the file", or "only show 1/16th of that", or "eliminate 3 out of 4 pixels in each direction". It shows every single pixel, eliminating NONE.

And are you clear on the 72 DPI myth?

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Dec 23, 2013 13:58:57   #
BobHartung (a regular here)
 
TheDman wrote:
On the sides, for me to view when I scroll. ALL of them. It does not "ignore many or most of the actual pixel data in the file", or "only show 1/16th of that", or "eliminate 3 out of 4 pixels in each direction". It shows every single pixel, eliminating NONE.

And are you clear on the 72 DPI myth?


Come on guys! The monitor displays at 72 or slightly more ppi (depending on type). This has nothing to do with the pixels in the underlying image. The number of pixels visible on the screen depends on the degree of magnification. Certainly at 1:1 (i.e. 100% of native image size) you are seeing every pixel, although you may have to scroll. At 25% magnification, I may be seeing 2 of every 3 pixels or less. The video card interpolates.

So if this is to continue, please consider the difference between monitor resolution and printing resolution. They are not the same thing.

HTH

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Dec 23, 2013 14:32:19   #
TheDman
 
BobHartung wrote:
Come on guys! The monitor displays at 72 or slightly more ppi (depending on type).


No, it does not. 72 PPI is a myth, that's the whole point.

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Dec 23, 2013 14:46:08   #
marcomarks
 
beauxPatrick wrote:
I just completed a shoot and they were Pet Portraits... shot under "cool" studio lighting (5000K) with out strobe. Av at 16 with shutter speed as low as 1/60 when zoomed... the slightest movement and I got a blur...

There is a reason for the "cool" lighting and no strobes... I am a Pet Friendly photographer and don't do anything to startle or upset the animals... 99% of my shots are good... a few did not turn out as well as I would have liked...

I had to have them printed at 16x24(20) and I saved each image at 16x24 at 288 dpi... when printed, I am disappointed in the quality of the enlargement... close up, they seem too soft... at a distance they look great... did I screw up by changing the dpi... even though I used a multiple of 72?

What should I have done...

beaux
I just completed a shoot and they were Pet Portrai... (show quote)


16X24 at 288ppi (not dpi) is 32MP of data to send to a printer. Did you have a 32MP camera file to start from? Did you use Genuine Fractals or Perfect Resize to increase the file size through its intricate process of interpolation of pixels before printing?

If you have a 16MP camera the photo files can't be quickly dialed up to 32MP for large printing without experiencing softness because you are printing at 200% larger than a 16MP file should be printed at for optimum results. If you cropped the original 16MP file, it is also now less than 16MP which makes the printed large result even worse. I'm also not sure where you learned that you need multiples of 72 when choosing a ppi for printing. I've never heard anything like that before.

A good "rule of thumb" is to size a file for printing using pixels in your editing program instead of inches, and choose 300ppi as a standard, although that doesn't directly related to dpi.

A printer prints at whatever dpi it is designed to print at and that may be 220dpi, or 240dpi, or any other number, but usually not higher than 300dpi. By choosing 300 PPI, not dpi, to calculate your needed file size you are sending the printer plenty of data to discard as much of it as it needs to while maintaining its maximum dpi quality. Unfortunately you are looking to create a print that should have 4800 pixels X 7200 original pixels sent to it and unless you have a very high resolution camera there aren't that many pixels available in the original pre-cropped file.

With that said, I have printed at 16X20 with fairly good success by not cropping the original RAW file, editing the RAW file as much as possible first, converting to TIFF and doing all other editing to the TIFF only, and not converting to JPG (with the lowest possible compression) until just before printing when nothing else needed to be done to the file.

Secondly, you need to get that 1/60th shutter speed up to more like 1/125th or even higher to stop motion blur caused by your subjects. You can push your ISO up to 400 or 800 to help you do that on most newer cameras. If Av means aperture on your camera, you don't really need f/16 for this work, f/8 should be enough and that allows more light into the lens which means your shutter speed is much higher to accomplish the same exposure.

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Dec 23, 2013 15:05:05   #
BobHartung (a regular here)
 
TheDman wrote:
No, it does not. 72 PPI is a myth, that's the whole point.


Are you saying that a monitor has unlimited resolution; that it has unlimited picture elements (pixels) with which to display a representation of an image. My Eizo ColorEdge CG301W has 2560 horizontal pixels in 25.25 horizontal inches of monitor surface. That works out to 100 pixels per inch (ppi). If I try to show a 7000+ horizontal pixel image I can either scroll or shrink the image. In the latter case, I cannot be displaying all the pixels. There is interpretation.

But, anyone can display (although perhaps not on one field of view) every pixel of an image if viewing at full size. Using one of the 5 megapixel monitors as work will display a whole lot more of a hasselblad image that will my ColorEdge. The Color Edge in turn will display a whole lot more of such a large image that my MacBookPro.

I am beginning to wonder if this is not just a matter of careful definition of exactly what we are talking about.

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Dec 23, 2013 16:30:25   #
Wall-E
 
f8lee wrote:
DMan, the Web may not care what resolution you use (since each monitor's driver will interpolate the image down to whatever its own native resolution is) but the shorthand way to save images for web use is to specify 72DPI which roughly translates to the 72PPI resolution of most basic monitors. Sure, you can save a 300DPI image sized at 4x6 inches and put it on a website, but since the screen only shows 1/16th of that (effectively eliminating 3 out of 4 pixels in each direction) what you've done is put a massive file online that will take a lot longer to download just to be viewed on a screen. In other words, the users who don't want to twiddle their thumbs waiting for a uselessly huge image to download do care.
DMan, the Web may not care what resolution you use... (show quote)


DPI. Dumb Photographer Information.

PLEASE stop talking about DPI in terms of image/file sizing.
Has NOTHING to do with it.
http://www.uglyhedgehog.com/t-147932-1.html

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Dec 23, 2013 16:36:52   #
TheDman
 
BobHartung wrote:
Are you saying that a monitor has unlimited resolution; that it has unlimited picture elements (pixels) with which to display a representation of an image. My Eizo ColorEdge CG301W has 2560 horizontal pixels in 25.25 horizontal inches of monitor surface. That works out to 100 pixels per inch (ppi). If I try to show a 7000+ horizontal pixel image I can either scroll or shrink the image. In the latter case, I cannot be displaying all the pixels. There is interpretation.

But, anyone can display (although perhaps not on one field of view) every pixel of an image if viewing at full size. Using one of the 5 megapixel monitors as work will display a whole lot more of a hasselblad image that will my ColorEdge. The Color Edge in turn will display a whole lot more of such a large image that my MacBookPro.

I am beginning to wonder if this is not just a matter of careful definition of exactly what we are talking about.
Are you saying that a monitor has unlimited resolu... (show quote)



No, I'm saying the number 72 never had magical meaning. It is no more significant than the number 62 or 52 or 32. And as far as the PPI meta tag in a digital file goes, it it completely meaningless. Too many people today think images on the web are 72 PPI, and I want to kill that myth.

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Dec 23, 2013 16:48:12   #
SharpShooter
 
krakkaz wrote:

Like boberic said, it's not about how anyone likes the shots but the customer.
Good work in my opinion.


Krak, lets not loose site of our photography.
Just because the customer is enamored with it, and pays us for it, does not make the work better, or even good.
Because our customers are NOT photographers, is not a reason to pass of poor work as good. If we are selling work, as professionals, our work needs to be darned good. Let's just hope our customer are getting what they paid for.
If you received a cheap knock-off in any product for full price, you would be screaming fraud !
Lets keep it in perspective, and do the best we can, and continue to get better. ;-)
SS

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