A question on filesizes and printing

harjtt

The last two days I've managed to get some decent shots together in RAW (Oly E1 RAW files are 10.2MP each) and then PP'd them into jpeg files using Lightroom. What I noticed with some of them was the final jpeg file size - approx 5-7MB in size (maximum detail and minimum jpeg compression). Now the usual SHQ jpegs straight from the E1 are approx 3-4MB each so I'm wondering will I be able to print these 5-7MB jpegs at an even larger size A3 or higher or is printing size still bound down to the sensors MP ?

Here's an example taken today - Jpeg file 6.9MP ISO200 f5@ 1/125s.




Cheers

HarjTT

:thumb

ziggy53

HarjTT,

It's a little hard to directly compare JPGs from RAW, and JPGs direct from the camera. Your processing can completely skew the file sizes. Take an original highly detailed JPG from the camera, process with some USM and note the change in file size. You will probably note a considerable increase from that singular change (I usually do.) There are also differences in the particular JPG engine used, as there is no singular JPG compressor specification.

It's especially difficult to equate a difference in JPG file size to any particular print size. Some images just translate to large print sizes, almost regardless of compression and file size. You almost always have to try it to see if you like a particular image at any particular size, and then, what surface you print on, the print technology used, the way the photo is framed and even how the print is displayed all have an influence.

I know you are looking for a more definitive and quantitative answer, but alas, none exists. As you attempt to print at different sizes, using different print methods, you will develop a "sense" for what will work based on experience.

In that vein, seek someone local you trust to view the full-sized distribution file(s) who has that experience, and trust their judgement for now. Think of them as a "mentor".

(... and just why aren't there any "womentor"s?) (Yikes, now I've done it!)

Best,

ziggy53

harjtt

ziggy53 wrote:

HarjTT,

It's a little hard to directly compare JPGs from RAW, and JPGs direct from the camera. Your processing can completely skew the file sizes. Take an original highly detailed JPG from the camera, process with some USM and note the change in file size. You will probably note a considerable increase from that singular change (I usually do.) There are also differences in the particular JPG engine used, as there is no singular JPG compressor specification.

It's especially difficult to equate a difference in JPG file size to any particular print size. Some images just translate to large print sizes, almost regardless of compression and file size. You almost always have to try it to see if you like a particular image at any particular size, and then, what surface you print on, the print technology used, the way the photo is framed and even how the print is displayed all have an influence.

I know you are looking for a more definitive and quantitative answer, but alas, none exists. As you attempt to print at different sizes, using different print methods, you will develop a "sense" for what will work based on experience.

In that vein, seek someone local you trust to view the full-sized distribution file(s) who has that experience, and trust their judgement for now. Think of them as a "mentor".

(... and just why aren't there any "womentor"s?) (Yikes, now I've done it!)

Best,

ziggy53

Hi Ziggy

Thanks for the advice as it was much apperciated. I think you answered my question pretty well and I'm pretty much happy with it.

Cheers

HarjTT

D

encosion

It's all about the canvas size and resolution... In answer to your question, technically all those files (including the RAW image) have the same canvas size and resolution - thus they will print at the same size... The amount of JPG compression used when creating a file affects the overall filesize (of course) but NOT the physical print size (canvas size and resolution)...

And I've heard it said a few times that using the "fine" or "super fine" JPG compression setting in-camera will make little visible difference on a print (than the "standard" or "high" settings), yet it'll eat up remarkably more filesize... I.E. There's no point in using the "super fine" settings unless you don't have a RAW image and or you're going to be editing the file before going to print...

JPG is of course a lossy compression, so if you're going to be editing a JPG file multiple times, the overall visual quality will get worse each time you save it... Of course if you have the RAW image file, you'd be editng that file in which case you'd only make a JPG when you're ready to print or publish to the internet...

I'm not sure what the exact threshold is... But that the higher the resolution, the less noticeable the difference... I.E. On a print out of an image from a 10Mpx camera, you wouldn't notice the difference between a highly JPG compressed file (say 50) and a very low compressed file (say 100 - like your example above)...

When you're dealing with low-res images (small canvas size & low resolution - 72dpi), the difference between 50 and 100 is however very noticeable...

DISCLAIMER: I've not printed ANYTHING out yet myself, but the theory (and 10 years of photoshop experience) makes sense to me... So do yourself a favour and try it yourself! Use a magnifying glass if you have to...