Nate Loc: Ann Arbor, Mi.

I am ready to burn images to a disk for a portfolio competition. Among the specified requirement instructions are three that cause problems; they are “300 ppi” and “Medium quality” on a Quality scale that ranges from 0 to 100. And, if these and all the other requirements are met:” the image file size will be approximately “1MB.”

My images started out as very large files and 32 bit. Some images meet these requirements with not problem others, however, result in files ranging from 1.5 to 2 MGs or larger. So, in order to approximate 1 MG, I have to either reduce ppi further or lower Quality severely. In such circumstances, I immediately drop to 250 pp, which I feel is insignificant sacrifice, but if in some instances I have to drop to 25 or lower on the “Quality” scale to even approach 1 MG. The question I have is which result least damage to the integrity of the images, reduce “Quality” well below “Medium”, or the further reduce ppi?

This question and request for further clarification was been emailed to the magazine editor, but I have yet to receive an answer. And, yes, my cpu screen has been properly calibrated.

EstherP

"300 ppi" is meaningless without knowing the overall dimensions of the image.
If an image is 300 x 300 pixels in dimension @ 300ppi, it will print at 1 x 1 inch.
If it is 1800 x 1200 pixels @ 300ppi, it will print as a 6 x 4 inch image.
If the latter image is dropped to 250ppi it will print at 7.2 x 4.8 inches.
When you save an image as a .jpg file, you are given a choice of quality, but the scale is 1 to 12. Medium quality would therefore be around 6. (I believe this scale is actually the amount of compression applied to image).
Maybe if you were to give us the exact dimensions in pixels, we would be able to get more help.
EstherP

Wall-E Loc: Phoenix, AZ

Calibration of your monitor is irrelevant to this.

PPI and DPI have NO meaning in digital images.
They ONLY apply at printing.

So, the real question is, what are the actual pixel dimensions are they looking for?
An 8x10 at their '300ppi' would yield a desired image size of 2400x3000 pixels.
And if you use a JPEG quality of 50, what file size do you get?

Nate Loc: Ann Arbor, Mi.

Re: size requirement: Base should seven inches, i.e, 1750 pixels. Most of my images are nearly square or slightly longer on the vertical sides.

Wall-E Loc: Phoenix, AZ

Sorry, 7 inches would give a length of 2100 pixels.
1750 pixels would give length of 5.8" at 300 ppi.

And where did the "Base should seven inches" (sic) come from?

Searcher Loc: Kent, England

There is the answer, 2100x2100 pixels 300ppi saved as a jpg at a compression factor of 8-10 could well be considered Mediam quality and saves at about 1 MB (depending on image complexity)

Nate Loc: Ann Arbor, Mi.

Wow---LR 5, gives 1750= 7 inches. I do have it set at inches, however. Although I shoot raw, they require jpeg conversions---which may play a role here.

The requirement for the base, i.e., bottom segment, comes from mag (B&W) specifications. I process either square or rectangular with long side up. I have been a winner in their past singles and portfolio contests and the submitted image, if printed in the mag it will be published full page or nearly so---otherwise, printed as seen through the viewfinder held laterally, a small half page format if published. I find that advisable for most purposes, other than gallery representations, and suchlike. And, images with the most detailed content so cause the main problems in meeting mag specifications

I am aware that 300 ppi is excessive, but these judges view the meta data, and I like to keep it close to specifications. I don't know why, say, 150 ppi or less isn't adequate for their purposes.

Question: What is the referent for the "Quality" scale. Resolution is my presumption---which can take us back to ppi count.

EstherP

1750 = 7 inches = 250 pixels per inch.
2100 = 7 inches = 300 pixels per inch.

On the quality scale, resolution is not the factor making a difference, compression is.
You can try this for yourself in your program:
Take the same image, "Save As" at a quality of 12 on the slider, do the same thing (with the same image) at a quality of 8, and again with a quality of 4.
Now check the dimensions and pixels per inch, as well as the size of the image in megabytes or kilobytes.
Do this and the difference immediately becomes obvious, and hopefully, understandable.
EstherP

PS - I use PSE for my photos.

OddJobber Loc: Portland, OR

Depends on which program. In Irfanview the quality is from 1 to 100 but I don't know how that affects file size.

Nate Loc: Ann Arbor, Mi.

Received a response from Contest Coordinator at B&W Mag. Their "Printer" requires these parameters to print the images, should my work be selected---they need a "Minimum" of 300 ppi/dpi, and anything under 2MG is acceptable. If I have to cut corners, then lower the "Quality" option. So, that helps.

FYI--most of my BW images have gone through LR 5 to enhance color, then to Silver efex for conversion to greyscale, then to PS, and finalized and sent out to desktop folder through LR 5. Some have been through HDR conversion, but one would be unable to tell--I like working with 32 bit files.

Thanks for your comments---will check w/ Adobe regarding conversion for inches to pixels.

Wall-E Loc: Phoenix, AZ

Check the samples about 3/4 of the way down the page.
http://en.wikipedia.org/wiki/JPEG

Wall-E Loc: Phoenix, AZ

What other information do you need?
300ppi means that it takes 300 pixels to make an inch.

BillLamp

Since you are using Photoshop...

Find out what the printed size of the photo will be.

With that in hand, open the picture in Photoshop and most likely will have to crop it.

"Tell" the crop tool what the sizes are AND you want 300 DPI.

Crop to the ratio you need and IMAGE-RESAMPLE to do the size to fit setting the DPI to 300.

Print shops normally want Adobe RGB so assign that color space, if you haven't already.

As for DPI vs PPI: A printer prints the DPI image using PPI which, on mine, can go to 2880x1440. Think of PPI being the number of pigment/ink dots per inch. OR Printed Points per Inch & Digital image Pixels per Inch.

WWW.SCANTIPS.COM has an excellent free tutorial on scanners but a lot applies to digital photos & printing.

TheDman Loc: USA

That's exactly what DPI is. PPI is the number of pixels in your photo that you want to place into an inch of paper space.

Nate Loc: Ann Arbor, Mi.

The latest word word from B&W competition coordinators is that the ambiguities and uncertainties which have concerned me arise because I use LR-5, rather than my PS as the last post processing program before burning to disk. I was told "...we use PS." It's more than a month before the deadline and will abide by their advice and see if that diffierence is significant. However that may be, the fact is I would have had no problems whatsoever if they had indicated in their specifications that anything less than 2MG is acceptable, and that 300 DPI is imperative. And,"Quality" level may be largely disregarded. My life was simpler as a "Film Forever" freak.