What resolution for an 8 x 10 print?

04/23/2004 05:32:53 PM · #1

I have been modifying my answer to this question as time goes by. For a while I was fairly happy with the 8x10 prints that I was making from 3.3 MPixel images. I got to the point where they just were not looking as sharp as I really wanted. This works out to a printing resolution of right around 200 dpi. Next I went to an 8 MPixel camera, now the 8 x 10 prints look very sharp. At this resolution it works out to a bit over 300 dpi on the prints. Today I started playing around with printing out stitched images that have 25 MPixel, the prints from these are very sharp. I am sure that I could resize the images down to something less then 25 MPixel and still get a great looking photo but as time goes by I am wanting more and more dip in my prints.

An important note to this is that I am fairly nearsighted and have been looking at the prints with my glasses off. I tend to see a bit more detail then some other because of being nearsighted, a prescription of â��4.00 in both eyes.

I am interested in what others are finding in terms of what the ultimate printing resolution is for them, where going any higher does not give a better looking image.

My parents make 8 x 10 prints using photos from their MPixel camera and they are very happy with the prints, to me they look vary blurry.

For those who want to look at my test image here is a link to it. The photo is not real exciting, just a view from our house.
Test Photo

pitsaman

Canon EOS-30D

Canon EF 50mm f/1.8 II

04/23/2004 05:38:10 PM · #2

8 x 150 = 1200
10 X 150 = 1500
Minimum Quality or 1.8 MP.

Good quality
8 X 300= 2400
10 X 300 = 3000 or 8.4 MP

With PSP 8 or Adobe PS you can resample the image as twice size and get minimum quality up to 16X 20 image with 3 MP camera !

TrollMan

Fujifilm X-T4

Fujifilm XF 35mm f/1.4

04/23/2004 06:46:44 PM · #3

Originally posted by scottwilson:

I am interested in what others are finding in terms of what the ultimate printing resolution is for them, where going any higher does not give a better looking image.

A normal human eye can't see the difference on images with a higher resolution than 200 dpi. Above 200 dpi, everything looks like continious tones. Keep in mind that some printers may lie and so what you thought were 200 dpi might not be as sharp as when you compare it to a 300 dpi print. If you generate two images on your on PhotoShop - one 200 and one 300 (same image) - you will not be able to tell the difference.

Message edited by author 2004-04-23 18:48:39.

Nazgul

Canon EOS-20D

04/23/2004 06:50:32 PM · #4

Originally posted by pitsaman:

dont quite get that mister pitsaman?
what do the numbers after the = stand for?

ScottK

Canon EF 28-135mm f/3.5-5.6 IS USM

04/23/2004 08:15:50 PM · #5

Originally posted by Nazgul:

dont quite get that mister pitsaman?
what do the numbers after the = stand for?

Total "dots" vertical and horizontal, from which he calculated the total MP for an 8x10 at 150dpi and 300dpi. The problem is, it doesn't really have anything to do with Scott's question.

Message edited by author 2004-04-23 20:16:23.

pitsaman

Canon EOS-30D

Canon EF 50mm f/1.8 II

04/23/2004 08:29:08 PM · #6

Originally posted by ScottK:

Originally posted by Nazgul:

dont quite get that mister pitsaman?
what do the numbers after the = stand for?

Total "dots" vertical and horizontal, from which he calculated the total MP for an 8x10 at 150dpi and 300dpi. The problem is, it doesn't really have anything to do with Scott's question.

His questionwas: "I am interested in what others are finding in terms of what the ultimate printing resolution is for them, where going any higher does not give a better looking image. "

300 dpi is ultimate quality for the human eye!

ElGordo

Sigma 18-200mm f/3.5-6.3 DC OS for Canon

04/23/2004 08:37:53 PM · #7

I have not been able to discern any improvement beyond 300dpi/color. One should bear in mind that the majority of cameras on the market use either RGBG or CYM+G color masks on their sensors.
So, for a typical RGBG mask, a six megapixel camera has 3 megapixel green, and only 1.5 megapixels for each red and blue. That reduces your 6 megapixel camera to a maximum effective color resolution of 1.5 megapixels.
However, luminance information in the image will still be 6 megapixels, and that is where we perceive fine detail in an image. There are some very pricy cameras that use 3 ccd elements, one for each color, and produce a noticeably sharper image.
Most inkjet printers are CYMK (four color printers) and will produce exceptional detail at 1440 or 2800 dpi, far more detail than the cameras are capable of recording, so the modern printers cease to be an issue as far as resolution is concerned.
The bottom line, as always, does the print look good to you!

04/23/2004 09:21:03 PM · #8

Originally posted by ElGordo:

In reality there is a lost of luminance resolution as well, this is due to how the Bayer pattern is used to make the RGB pixels as well as the fact that resolution has to be somewhat limited to avoid color aliasing.

04/23/2004 09:24:59 PM · #9

It is clear that printing with resolutions beyond 300 dpi will make a sharper print. The question is how many people will be able to perceive this extra sharpness. Below are two 600 dpi scans that I did of my test photo, one printed at about 600 dpi and the other resized to printout at about 300 dpi. There is clearly more detail in the 600 dpi image, the question is how many people will see this difference. I am so nearsighted that I can see the difference between the 300 and 600 dpi prints but most people with normal eyes probably would not.

If anyone want to try printing out my file you are welcome to download it, it is not too large, about 2 Mbytes. It does make an amazingly sharp 8 x 10 print. BTW I am printing using a Cannon i560, not the highest end printer but one with a fair bit of resolution.

Test photo

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

04/23/2004 09:36:43 PM · #10

If storage and processing/printing time are not an issue, then just use the maximum amount of data you have available -- why not? If they are issues, then preferably use 300 dpi, and as low as 150 dpi in "emergency" or "FPO" situations.

I would not resample up from the native size to get additional resolution.

If you are going to use the image for a halftone (offset printing) then it is preferred that your file's ppi be at either 2x or 1.5x the "screen ruling" your printer will be using. 300 ppi is completely typical in these situations ....

Message edited by author 2004-04-23 21:37:56.

04/23/2004 09:42:45 PM · #11

Originally posted by GeneralE:

I guess what I was more thinking of was how many pixels would a digital camera have to have before any more pixels made no difference in the perceived sharpness of an 8 x 10 print. I use to think that this number was around 8 Meg but now I am rethinking this based on prints that I have been doing of late. I am also finding that this number will be different for different people. My guess is that young eyes as well as nearsighted eyes will see improvements in image quality that others might not.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

04/23/2004 09:52:17 PM · #12

Based on information I used in going the other direction to make slides ... how many pixels does it take to expose a 35mm frame to the equivalent resolution of light from a lens hitting the film (roughly equal to the size of the film grains)? For ASA 100 slide film, the techs stated that this value is about 4096 x 2732 pixels (however many megapixels that is), and is about a 32mb file in uncompressed (e.g. 8-bit RGB TIFF) file format. Right now, I think the only digital cameras at this resolution are super-expensive camera backs (e.g. Leaf).

Note though, that we were instructed that this resolution was rarely needed to get an acceptable slide, and we almost always ran the imager at half that resolution (2048 x 1366 pixels).

This all assumes that you'd be satisfied with an 8 x 10 print from a 35mm negative ... if not then I take it all back :)

Message edited by author 2004-04-23 21:53:48.

Bobster

Canon EOS-20D

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

04/27/2004 06:29:14 PM · #13

a 10x8 is 3000x2400px @ 300dpi

bruski

Canon EOS-50D

Tamron SP AF 17-35mm f/2.8-4 Di LD Aspherical IF for Canon

04/27/2004 06:37:16 PM · #14

It kind of depends on the printer you are using. The Fuji Pictrography makes almost flawless prints at anything above 150 dpi. My newer R800 however, I can see the difference between scanned and digital. I can also see the difference between 300 dpi and 600 dpi.

Mick

Canon EOS-5D

Canon EF 70-200mm f/2.8L IS USM

04/27/2004 06:52:13 PM · #15

Originally posted by pitsaman:

Good quality
8 X 300= 2400
10 X 300 = 3000 or 8.4 MP

Wouldn't that be 7.2 MP?

2400 X 3000 = 7200000 total pixels.

Divide the total pixels by 1 megapixel (1,000,000 pixels)
7200000 / 1000000 = 7.2 MP

--Mick

Natator

Canon EOS-5D

Canon EF 24-105mm f/4.0L IS

04/27/2004 06:58:25 PM · #16

How does all that tie into the printers specs though?

I think from memory that my printer, as do many, boast being able to print at 14800 (or something) dpi, even the most basic ones are 740.

If the best the human eye can see is 200, even call it 300 ..... what do these figures mean for the printers?

Obviously there is no benefit of saying how wonderful a printer is at 1400000000 dpi if the eye can opnly see 200. Marketing or is there something else involved?

04/27/2004 07:18:05 PM · #17

Originally posted by Natator:

The printer needs higher resolution to make the colors looks smooth. This is because printers make different color levels by the varying the spacing between the dots. The more dots per inch you have the smoother you photo will look. A printer that uses 7 inks will need fewer dots per inch then one that uses 4, three of the inks are lighter.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

04/27/2004 07:20:24 PM · #18

The number of spots the printer can image (laser spots, ink droplets, whatever) determines how accurately the printer can reproduce those 2-300 dots/inch the human eye can see. This is also the basis of halftone printing (offset), and why photos in books look better than photos in the newspaper.

To give you a mathematically simple example:

Printed dot size: 120/inch

Printer spot size: 600dpi (typical laser printer) -- each printed dot is made up of a 5x5 grid of printer spots, so that can have any of 25 values, depending on how many of those 25 spots are actually exposed by the laser.

If you move up to a 1200 dpi printer (inkjet or low-end imagesetter), each printed dot is now generated from a 10x10 grid of lasers spots, allowing the printed dot to have any of 100 values. With a 2400 dpi imagesetter like I use at work, each of those printed dots is made up from a grid of 20x20 machine spots, so it could have any of 400 values.

Newer printers don't work with the same fixed grid of printed dots, so it's not exactly the same, but the general principle should always hold, that the higher the resolution, the smoother the range of tones which can be achieved at any given size/frequency of printed dot.

The most shades of any color you can get with 8-bit (RGB) files and PostScriptÂ® is 256, so any printer resolution which achieves more than 256 shades is probably superfluous.

Most inkjets are based on multiples of the original 72dpi computer resolution: 720, 1440, 2880.

Message edited by author 2004-04-27 19:22:38.

ElGordo

Sigma 18-200mm f/3.5-6.3 DC OS for Canon

04/27/2004 07:23:47 PM · #19

Originally posted by Natator:

text

Obviously, yes! To achieve gradations of color and shading the printer must begin spacing the dots printed. For example, if a green tree leaf has several shades of green, then other colors are combined in a pattern to get green. The density of the dots will determine the lightness or darkness of the shades.
If there is a great range of shades in an image, the printer runs out of possible combinations to faithfully represent the required colors. That is why higher dpi printers produce better results. Dye sublimation printers combine the pigments before printing on the page and can therefore achieve a more faithful
representation with a smaller dpi. Inkjet printers do not combine the dots at all, but print each color dot separately. HP attempted to overlay ink dots with one of their 'photo-realistic' printers but the result was not terrific.

Natator

Canon EOS-5D

Canon EF 24-105mm f/4.0L IS

04/27/2004 09:37:23 PM · #20

Thanks guys, that clears that one up. Just flipping confuzzling that they both use the term DPI but they do not mean quite the same thing.

Rooster

Sigma 28-105mm f/2.8-4.0 Aspherical for Canon

04/27/2004 09:44:07 PM · #21

I work off od TIFF converted from RAW. When I convert the jpeg it looses the dpi set on the TIFF. Any thoughts on why this happens & how to avoid it?

jab119

04/27/2004 10:47:33 PM · #22

you guys are making my head hurt.....all I know is I send off my pics to print 8x10, 4x6, 5x7 an one large pano 24x30 (or somethng like that) and they look great to me and to others as well, no resampling or any of that fancy stuff

I do VERY little post processing, and only shoot in medium jpg in my D60 (2048x1360, what is that 2.7MP).

The guys at the camera shop where i get the prints done sometime have a hard beleiving they are from a digital camera....not sure if they are just blowing smoke up my you know what....but I had to argue with the guy one time kinda funny whan I went out and got the D60 and showed him the pic that was still on the camera....

James

ElGordo

Sigma 18-200mm f/3.5-6.3 DC OS for Canon

04/27/2004 11:53:52 PM · #23

Originally posted by Rooster:

I work off od TIFF converted from RAW. When I convert the jpeg it looses the dpi set on the TIFF. Any thoughts on why this happens & how to avoid it?

text

The image pixel density should not change, that is, if the image was 3000 X 2000 pixels in the TIFF format then it will still be 3000 X 2000 pixels in Jpeg format. But the jpeg compression algorithm will make the image filesize much smaller depending on the compression quality selected.
Smaller files mean lower quality and vice versa.
If the image DOTS/INCH changes during the compression, that does not affect the image content, just the area required for printing.
A 5 X 7 inch print at 600 dpi will have exactly the same image content as a 10 X 14 image at 300 dpi. Most image processing software allows you to specify the dots/inch for printing. In Photoshop, the image size and resolution can be selected under IMAGE > IMAGE SIZE.