PNG or JPEG for print, whats best??

Mark Snelling Mark Snelling 42 posts

Hello there, have uploaded some of my pics in PNG format about 50 mb in size, but have also got 10mb JPEGS saved as well, what format prints best for large prints.

Thanks for your answers

Mark

Luis Enrique Cuéllar Peredo Luis Enrique C... 563 posts

I personally avoid JPEGS in general, so I think PNG is better, but always remember that if you’re gonna use PNGS for print do not use the interlaced option, leave it as “no interlaced”.

Mark Snelling Mark Snelling 42 posts

Thanks for the reply, I agree too and do not interlace my PNGs but read several different views on this subject, with many favoring JPEGS for print, maybe a redbubble team member could explain whats better for them to print regarding quality differences at large sizes, I have always thought TIF format would be better for large prints, but redbubble doesn’t have this option on upload.

Luis Enrique Cuéllar Peredo Luis Enrique C... 563 posts

I agree! TIF is way much better when it comes to print quality, and indeed it would be better to ask an admin directly.

DoreenPhillips DoreenPhillips 5781 posts

@Tordo……….sorry this is a bit off topic …well in a way it is and isn’t…………I have just found out that most digital cameras have a set 72 ppi as I found out trying to upload to a site ,that would only take 300ppi…………..Do I have to change the Image size as well and does it really matter when uploading to RB?……Maybe I should post this somewhere else………………..Thank you for the no-interlace PNG question and answer…………….xxx

joan warburton joan warburton 3149 posts

My Cannon was 72 and my Fuji is 72, but I’ve had two Nikons and they’re 300dpi.

efikim efikim 815 posts

as I’ve explained somewhere else on redbubble, the ppi recorded in the file has next to no meaning – its simply a hint to any application reading the file to what resolution the author expects it to be displayed/printed at. In practice, of course, the author doesn’t know or care, however as the field is there in the spec it has to be set to something. All that actually matters is how many pixels are present, and what space they are actually displayed/printed over.
The only difference between a 3000×2000 pixel image set to 72 dpi and a 3000×2000 pixel image set to 300 dpi is that this field is set to a different value. It doesn’t change the pixels in any way.
Redbubble don’t care what the ppi is set to; they do care how many pixels there are.

Kathleen Stephens Kathleen Stephens 7234 posts

Images have to be uploaded to RB over the web. Not all software can handle tifs. They are not built the same as jpgs, pngs or gifs. Yes, the tif is the extension of choice for commercial layout software and printing along with eps and bitmaps, but many printers now accept jpgs.

If I shoot a RAW/NEF image the size is 5.22. When I convert it to a tif, the size jumps to 17.2. If I save it as an umcompressed jpg the file size is 17.2. So as long as there is no compression introduced to a jpg, the image is pretty much equal to a tif.

PNG was intended to replace the older GIF and TIFF formats for use on the World Wide Web and in image editing. A main advantage of PNG compression is that it’s completely loss-less; this means that all compressed data is maintained and can continue to be fully edited, which can’t be done with GIF and JPG formats. PNG supports 48-bit true color and 16-bit grayscales, and saving, editing, and transferring images will not degrade their quality.

JPG is still the best choice for photos.

efikim efikim 815 posts

this means that all compressed data is maintained and can continue to be fully edited, which can’t be done with GIF and JPG formats

true for JPG, not necessarily for GIF files – it depends on the compression options you choose. For some graphic images a losslessly compressed GIF can be much smaller than a compressed JPG, though this is not usually the case for photographs.

joan warburton joan warburton 3149 posts

“It doesn’t change the pixels in any way”

No, but it changes the size of the printed image if you want to maintain quality.

An 1800 × 1200 resolution image can be saved as 300 dpi or 100 dpi. At 300 dpi it is 4 × 6 and at 100 dpi it is 18 × 12.

However, at either dpi, the image is still 1800 × 1200 and will still have approximately the same file size.

Some stock photo sites require uploading at 300dpi.

DoreenPhillips DoreenPhillips 5781 posts

My photo’s upload at 3456X2592 pixels and it seems to depend on the programme ie: Picasa or PS that the ppi/dpi changes?………..x

Mark Snelling Mark Snelling 42 posts

Thanks for your answers guys and gals, but visually not technically is the finished article i.e large print better in PNG or JPEG ?, having never printed a large PNG v JPEG comparision I can’t comment, maybe I should do that when I have some cash LOL.

May I also say as a newbie to redbubble the community here is the best, website build and layout 1st class.

Keep up the good work and keep ya fingers on that shutter button…..

Kathleen Stephens Kathleen Stephens 7234 posts

For printing, jpg for photos and pngs for graphics and Ts as a rule. I have not used the png for photos here nor have I printed photos as pngs at home, so I really can say that there is a difference, although I would expect the photo quality to be a little less with a png depending on the type of photo.

prbimages prbimages 1900 posts

Kathleen: A main advantage of PNG compression is that it’s completely loss-less; this means that all compressed data is maintained and can continue to be fully edited, which can’t be done with GIF and JPG formats. PNG supports 48-bit true color and 16-bit grayscales, and saving, editing, and transferring images will not degrade their quality. JPG is still the best choice for photos.

Kathleen, I don’t understand, if PNG has all those advantages that you mention, what basis do you have for the statement “JPG is still the best choice for photos”?

Confused, prbimages :-)

InPort InPort 2939 posts

NOW HEAR THIS! NOW HEAR THIS!

In my home town of Port Macquarie, NSW, Australia we have a very successful intra and international professional and commercial photography and printing business. All their print work is done on line. They require images to be jpg set to High Quality 8. (The owner told me once that 8 is a bit of overkill and that Medium Quality 5 would suffice but High sounds good to the customers). I have had many colour and B&W 8×8, 8×10 and 8×11 photographs printed by them and the quality is excellent. I have also had 12×18 prints made by Harvey Norman and they require jpg images.

Here on RB we are asked to send images as jpg, 3840pixels for the largest dimension and at the highest quality possible. (I use Maximum Quality 12).

I know of other commercial printing companies that work on line and they all use jpg so in my ’umble opinion PNG, PSD, TIF, DNG etc etc etc means naught in the scheme of things at our level. This is especially true when you consider that RB offers Posters.

Strangely when printing my own photographs, (up to A3+), I use my archival psd files. 8-)

Something to think about.

GB
D!

joan warburton joan warburton 3149 posts

Do .jpg images lose their viewing quality over time? I’m talking about images posted on internet years ago, not the ones opened constantly on your computer. I know these lose quality over time.

Some old images posted on a website ten years ago seem darker and grainy.

InPort InPort 2939 posts

As far as I know the only time you lose quality in jpg images is when they are altered and saved time and time again. If you have processed and made a psd, png, dng, tif etc image and then save it once as a jpg there is no loss.

As for degradation of jpg images on the web, I can’t see how that could happen as it is all just ones and zeros. Perhaps what you are noticing is gradual degradation of your monitor or eyesight or both. (?) 8-)

GB
D!

Aerophant Aerophant 898 posts

The artefacts and colour shifts that jpg introduces are not as visible on most photographs as they are on graphics that have flat areas of colour. It’s better to use png for this type of artwork. Jpgs lose quality each time they are resaved. They can’t deteriorate by sitting on a computer doing nothing.

prbimages prbimages 1900 posts

Joan: Do .jpg images lose their viewing quality over time? I’m talking about images posted on internet years ago, not the ones opened constantly on your computer. I know these lose quality over time.

No. Digital images are, at the lowest level, just a series of numbers. As such they cannot and will not change with time.

For the same reason, opening files frequently on your computer does not affect them in any way. (You are probably thinking of the common claim that JPG images lose quality if they are frequently saved. This can happen if you open a JPG file in a photo editor, and make some changes, and then save it again.)

Cheers, prbimages :-)

prbimages prbimages 1900 posts

Dennis: Perhaps what you are noticing is gradual degradation of your monitor or eyesight or both.

Ha ha! I can identify with that!

Geez, sometimes you need to be quick responding to a post here, lest the plebs get their responses in before you …

Aerophant Aerophant 898 posts

Prb, the deterioration will still happen if no changes are made. It’s the saving process that causes the deterioration.

prbimages prbimages 1900 posts

Aerophant: Prb, the deterioration will still happen if no changes are made. It’s the saving process that causes the deterioration.

Hmmm, you may right about that … I may check it out further when I’ve got a bit of time.

joan warburton joan warburton 3149 posts

I was wondering if it’s the jpg images or the possibility that the programs I used and the monitors were older models and they’re much better today. Thanks. I’ve been taking things down a little at a time and replacing them. They’re much brighter and colors are truer now. Everything was so dark back in the stone age and just seemed to be getting darker. LOL!

geetwee geetwee 2289 posts

the deterioration will still happen if no changes are made. It’s the saving process that causes the deterioration.

True but why save something if you haven’t changed anything? I use Irfanview (it is also an Editing program despite the name). You can do what you want with an image but unless you specifically select Save from the File menu all changes are lost when exiting.

Kathleen Stephens Kathleen Stephens 7234 posts

Ten years ago the file size we could up load to the web was limited, so more compression was needed. That would make a difference also.

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