more on ideal image rez 180 or 360

[jdiakiw]

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I was intrigued by the lengthy discussion on david adamson's 30 x 40 image and his comments on 180 vs 360 for epson prints. I opste in my other favourite forum photo.net the follwing comments form david and here are some of the responses. . .now I am really confused

 

 

Surprising info regarding Epson print sizing

 

jerry diakiw, Jul 14, 2007; 02:59 p.m.

 

I have asked some questiosn recently regarding ideal print size for my epson 2200. Caleb conditi put me on to a forum discussion on the leica forum regarding a master printer printing a 30 x 40 in from a 10 mp image

 

one poster wrote:

 

Any of you not familiar with David Adamson should check out the following links

 

DP&I.com: Featured Printmaker - David Adamson

 

ADAMSON EDITIONS | ADAMSON GALLERY

 

He is one of the world's preeminent digital printmakers."

 

Looking at his prints and his print studio in washington dc is very impressive he uses many state of the art printers and prints BIG.

 

In one post david wrote: "A quick tip for epson users - the printer makes its best imaging at either 360 dpi or 180dpi the difference is really minimal. Try 180dpi and you will be surprised by the results 180 at 27 x 40 (that is the M8 format) is about 100 megs as opposed to 200megs for the 360 and the file does not have as much interpolation. Shorter RIP times etc,etc"

 

later in another post in the same 11 page thread he wrote again:

 

Yes, it is true of all of the Epson printers I have done extensive testing and print comparisons and the difference is minimal and then only if you know what to look for, for instance one can print a file at 180 that is subjectively superior than one at 360 depending on the scanner. Also whether one chooses to print at 1440 or 2880dpi has a similar effect ie. on a gallery wall under glass probably no one would be able to detect any difference- under close scrutiny by an expert, yes. You have to take in all of the factors if you are producing 11x14 or 16x20 exhibition pictures then use 360 and 2880, if you are producing a 40 x 60 prints that will be viewed from 2 or 3 feet the no difference will be seen at 180dpi Again you choose the most appropriate workflow for a variety of reasons, viewing distance, file size and availability and subject matter - one can print clouds as large as you like, however, close up's of fine textural details may limit you to higher resolutions both at the source and output stages. Experiment and have fun we are in the great age of vintage digital!"

 

If youo want to read any f the discussion abouot the 30 x 40 in print with many comments about sizing and extrapolation here is the link"

 

(link)

 

Jerry in toronto

Answers

 

Bruce Watson, Jul 14, 2007; 05:51 p.m.

 

This is true only if the print will be viewed from "appropriate viewing distances" meaning you stand away from the print a distance about equal to the diagonal of the print.

 

I'm shooting 5x4 film and drum scanning it for 125 x 100 cm (about 50 x 40 in) prints. I've run tests starting from a drum scan at output size with an output resolution of 360 ppi (at RGB 16 bit/channel that's around 1.5GB IIRC). I made a series of 30 x 30 cm (about 12 x 12 in) prints from a detailed section of the image. First was a full rez 360 ppi print. Next I downsampled to 300 ppi output. Then I went back to the full rez image and downsampled to 240 ppi. Again, to 180 ppi.

 

These I pinned to my "proofing wall" side-by-side under the same lighting. From up close (about 25 cm away) it was difficult to see the difference between the 360 ppi print and the 300 ppi print. It was considerably easier to see the detail softening up in the 240 ppi print. The 180 ppi print was pretty ugly.

 

From the "correct viewing distance" of about 140 cm (about 55 in) I couldn't tell the difference between the 360 ppi print and the 300 ppi print even though I knew what I was looking for. I could just see the smallest difference between the 360 ppi print and the 240 ppi print. I could see the difference between the 360 ppi print and the 180 ppi print but it wasn't that big a difference and it was no longer "pretty ugly."

 

All I'm saying is, viewing distance is critical.

 

From watching people look at photography in museums and galleries however, I have to tell you that many (most?) people like to walk right up to big prints and give them a close look. They want to see how much detail you are actually carrying in the print.

 

Moral of the story? I now scan for these big prints with an output resolution of 300 ppi. This makes for a "nose sharp" print. Is it overkill? Not for me. Clearly, YMMV.

 

Bob Michaelsphoto.net patron, Jul 14, 2007; 06:27 p.m.

 

Jerry: Let me suggest you follow Bruce's lead. Crank up YOUR printer. Make YOUR prints. Decide for YOURSELF. There are a lot of variables here.

 

One thing I have concluded is that all correct photo answers begin with "Well, it depends........"

 

Ronald Moravecprolific poster, Jul 14, 2007; 08:31 p.m.

 

just crop out a center and make an 8x10 at 180/240/360.

 

Edward Ingoldphoto.net patron prolific poster, Jul 15, 2007; 12:28 a.m.

 

"180 at 27 x 40 (that is the M8 format) is about 100 megs as opposed to 200megs for the 360..."

 

A file with twice the resolution is four times as large. I'm not surprised at this lapse considering the other unfounded and often preposterous claims by the source of this mistatement.

 

I would not print at 180 ppi because fine detail, particularly the eyes of a subject, look granular at such a low resolution. A 27x40 INCH print from 35mm film would be ugly, regardless of the camera used. It is well beyond the limits of good taste for a 10MP camera, and possibly a 16MP camera at any resolution. Perhaps we are talking about a 27x40 CM print, omitting the units for some reason. In that case, a 4MP camera would suffice.

 

A 30x40 inch or 40x60 inch print is in the realm of 4x5 film or larger, unless there is some physical barrier that keeps viewers at least 18 feet away. It sounds like someone stayed at an Holiday Inn Express ;-)

 

The only difference I observe between and Epson print at 2880 dpi vs 1440 dpi is that the higher resolution applies more ink and has higher saturation and possibly an higher DMax.

 

Frans Waterlander, Jul 15, 2007; 01:54 a.m.

 

Here we go again with the myth that at higher resolutions a printer uses more ink! More ink would mean darker prints as the ink absorbs light; more ink, more light absorbed, darker print.

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[stunsworth]

Here we go again with the myth that at higher resolutions a printer uses more ink! More ink would mean darker prints as the ink absorbs light; more ink, more light absorbed, darker print.

 

Well it depends <grin>. More ink would not mean darker prints if the paper absorbed the ink. It's the surface of the ink that absorbs the light. a jar filled with half a litre of ink wouldn't look any darker than a jar filled with 100ml of ink.