weird jpeg question - DPChallenge Forums

Canon EF 24-105mm f/4.0L IS

09/02/2014 10:22:21 PM · #1

Hey dudez,

Entering a photography contest, and the rules state that the image should have an approximate size of 3000x2000 pixels.

but it also says the jpegs should be AT LEAST 2 megabytes. It also says a maximum of 4 megabytes, but larger files will be accepted.

Here is my problem: the picture im entering is way less than 2 megabytes at 3000x2000 pixels.

Is there any way I can increase the file size besides increasing the pixel dimensions? I know the point of jpeg is to minimize file size, but it has to remain jpeg format.

scalvert

Canon EOS-5D Mark III

09/02/2014 10:37:53 PM · #2

Just go bigger than 3000x2000. It says "approximate," and the file size ramps up quickly.

Message edited by author 2014-09-02 22:58:03.

scarbrd

Leica M10

Leica 35mm f/1.4 Summilux M Aspherical MF - Black

09/02/2014 10:40:49 PM · #3

I can't imagine why they would have a minimum file size. That just doesn't make sense.

Save it at the highest quality jpg (12 in Photoshop) and that's all you can do except increase the pixels.

Message edited by author 2014-09-02 22:41:15.

Canon RF 24-70mm f/2.8 L IS

09/02/2014 10:42:43 PM · #4

thanks guys, i think going bigger might be the way to go, i suppose. since i have to break one rule, might as well break the more ambiguous rule.

kirbic

Canon EOS R5

09/02/2014 10:47:05 PM · #5

So if you have a 6Mpx JPEG that is below 2MB, you have an image with a lot of very smooth, detail-free area. I think Shannon has the right idea. Increasing image dimensions ramps up file size by the square of the increase, e.g. if you increase by 10% to 3300 x 2200, your size should increase about 21%. Another option that I suggest somewhat tongue in cheek is to add a very small amount of noise. That will increase size rather dramatically while being imperceptible, or barely so, to the viewer.

09/02/2014 10:50:35 PM · #6

Originally posted by kirbic:

Yes, I already played with the noise idea, it is a good one. doesn't work for the image though, and it's very noticeable, because most of the image is a pure black background (as you already predicted)

09/03/2014 07:24:12 AM · #7

What is your ppi density? It doesn't matter for Internet display, but if the contest is run by a magazine, they may need a 300 ppi image for print purposes.

09/03/2014 08:46:58 AM · #8

240, but changing ppi doesn't really change the size, does it?9

Canon EF 24-105mm f/4.0L IS

09/03/2014 09:07:22 AM · #9

Originally posted by LanndonKane:

240, but changing ppi doesn't really change the size, does it?9

File size, yes. I am NOT suggesting you convert your current image to a higher ppi, as you would lose some quality due to resampling. Go back to your original image capture. It should have been exported to your computer at 300ppi or higher. Retain that resolution for print purposes. If the destination is a printer and a high resolution print, you will find 240 ppi to be marginal.

Message edited by author 2014-09-03 09:08:10.

scalvert

Canon EOS-5D Mark III

09/03/2014 09:41:10 AM · #10

Originally posted by LanndonKane:

changing ppi doesn't really change the size, does it?

No, it doesn't. The pixel density is not relevant here. If the publisher want to use your photo for print, they'll convert it to 300dpi / CMYK themselves and 3000px is plenty.

Canon EF 24-105mm f/4.0L IS

09/03/2014 09:55:37 AM · #11

Originally posted by scalvert:

Originally posted by LanndonKane:
changing ppi doesn't really change the size, does it?

No, it doesn't. The pixel density is not relevant here. If the publisher want to use your photo for print, they'll convert it to 300dpi / CMYK themselves and 3000px is plenty.

The pixel density is not relevant for Internet display devices. It is relevant for physical print devices. Likeâ�¦ very relevant! I think the organization is simply trying to require high resolution images that do not require conversion and resampling. But, I'm just offering an opinion.

scalvert

Canon EOS-5D Mark III

09/03/2014 10:06:56 AM · #12

Originally posted by hahn23:

The pixel density is not relevant for Internet display devices. It is relevant for physical print devices. Likeâ�¦ very relevant!

Pixel density not relevant to LanndonKane's issue. I'm well aware of printing requirements (professional print production has been my day job for 30+ years). 3000px is plenty for a typical magazine regardless of the original file's density, and it's not uncommon for high-res stock photos to come in at 240ppi or even 72ppi.

09/03/2014 10:13:18 AM · #13

PPI/DPI is just intructions that get sent to the printing device. It can easily be changed at any time, without resampling.

09/03/2014 10:39:31 AM · #14

Great! Be sure to show us your contest winner when it scores top position. Best wishes!

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

09/03/2014 11:30:42 AM · #15

Originally posted by hahn23:

Great! Be sure to show us your contest winner when it scores top position. Best wishes!

LOLZOS

GeneralE

Canon PowerShot S3 IS

09/03/2014 12:50:12 PM · #16

Originally posted by scarbrd:

I can't imagine why they would have a minimum file size. That just doesn't make sense.

Save it at the highest quality jpg (12 in Photoshop) and that's all you can do except increase the pixels.

I'm in this camp -- if the pixel dimensions meet their requirements and you save at the highest-quality JPEG setting you should be fine -- I'd just attach a note saying that's what you've done, and that the (commpressed) file is smaller (in bytes) than what they list because it is largely monochomatic and noise-free.