I need bigger Jpegs from Tiffs

[irlien]

Hi everyone!

My clients require 2MB jpegs @ 300dpi for print. Seems reasonable, right?

I shoot RAW and process as 16 bit Tiffs. After editing in Photoshop (cc2014) I end up with files around 350MB. However, when I save as Jpeg, I very often get files of 1.5MB which my clients reject. So I give them the Jpeg2000 format which is a longer process to complete.

Am I doing something wrong? Is there a mathematical equation to calculate the Tiff to Jpeg conversion?

Thanks for any clarification.

Neil.

[Black Pearl]

You get 350MB TIFF files - how?

What pixel dimensions do your shots have to get such a gigantic file? Also just about any native pixel count file will give a JPEG of around 2MB.

Explsin your exact process.

[ajohnw]

And adding to Robin. What size of jpg pixels wise? What jpg quality level? Given the size of the TIFF's what camera may be of interest as well.

John
-

[irlien]

Well, I use a 5dII and layering in Photoshop adds up quickly. The Tiffs are 3744x3744 and I select maximum quality for Jpegs.

[BrianA61]

I have a 5dII also but I only use PS for HDR or pano combining. Then, I adjust in LR and export at max quality in jpeg. My jpegs usually turn out to be anywhere from 5-12MB. That is converting a TIFF file as large as yours to jpeg. Might want to double check the original TIFF file size and also double check your export/conversion settings. I don't know that much about converting in PS but the process should be close to, if not, the same as LR conversion.

[ajohnw]

I'd expect TIFF's from a 5D II to come out at around 100mb so I suspect you mean the size of a file to save all of the PS settings or it's a panorama.

JPG size depends on the size of the image and to some extent the detail in it plus the quality settings. I don't use Adobe products but use a 95% quality setting.

John
-

[Kodiak]

Is there a mathematical equation to calculate the Tiff to Jpeg conversion?

Yes there is a mathematical equation to calculate the Tiff to Jpeg conversion: 1:1. !!!

I see no surprise in tiff files (in 16bit) reaching that size under given conditions.

The basic point to understand if that files size is always expressed in ppi. So,
any given file in any format will be converted to the same ppi by default unless
you changed the conversion parameters. The original MB size will differ to bigger
or smaller but the ppi will (should) remain the same unless…

So check out your conversion setup and you'll find where the hiccup is.

[Kodiak]

Well, I use a 5dII and layering in Photoshop adds up quickly.

The make and model of camera is irrelevant! All that counts is the final file size in ppi.

The Tiffs are 3744x3744 and I select maximum quality for Jpegs.

This conversion tiff to jpeg should render the same image size in ppi. The JPEG
image size in MB will vary according to the level of compression you will want
in your final rendition.

[ajohnw]

Kodiak. I'm curious. If I go raw to 16bit tiff 16mb camera I get a file around 80mb in size and the ppi dpi or what ever has nothing to do with it. Doesn't on jpg's either - as far as the screen is concerned as that is the part that sets the size of the image.

Am i missing something?

If I upscaled the tiff obviously it would get bigger but 16mp of the camera is 16mp.

John
-

[DanK]

Neil,

I think you probably can forget both dpi and ppi. Keep in mind that there are no "inches" in a file, so there is no number of pixels or dots per inch. File size is expressed either in the number of pixels in the image or the storage space it requires.

The size of your file with layers is also irrelevant. You will lose all the layers in creating a jpeg. Only two things are relevant: the size of the image in pixels (not pixels per inch), and the level of quality or compression you select in creating the jpeg.

To illustrate what you should expect, I just took a raw file from my 50D. It was roughly 20.6 MB and 4752 x 3168 pixels, that is, 15.05 MP. I then converted it in LR to a 16-bit TIFF. That was still 4752 x 3168 pixels, but 90.4 MB. I then created the highest quality jpeg twice, once starting with the TIFF in photoshop and once from the raw file in LR. The algorithms are apparently slightly different, but not much: one was 7.1 MB, and the other was 7.2 MB.

The size of a jpeg will vary somewhat depending on the content of the image, but unless you have cropped a lot or resized a lot, any highest-quality jpeg from your camera should be much bigger than that. I just took a random raw image from my 5D3, and it yielded a jpeg of 16.5 MB.

The 300 ppi figure comes into play as a setting for the printer. That's the native setting for my Canon printer. So, to print any given size, the image has to be up- or-downsized so that the pixel count matches the dimensions in inches times 300. Some software will do this for you automatically, while other software requires that you do it manually.

So, I would go back to the beginning: what does your client need? If they simply need a jpeg high enough in quality to print at 300 ppi, I would just export a fairly high-quality jpeg, which will be more than ample unless they are printing very large. If they want you to do the resizing, you need the dimensions, and then do the arithmetic to calculate how much to downsize the file. Then output the highest quality jpeg, and you should be fine.

[Kodiak]

Kodiak. I'm curious. If I go raw to 16bit tiff 16mb camera I get a file around 80mb in size and the ppi dpi or what ever has nothing to do with it. Doesn't on jpg's either - as far as the screen is concerned as that is the part that sets the size of the image.
Am i missing something?
If I upscaled the tiff obviously it would get bigger but 16mp of the camera is 16mp.

I am not sure to understand your question but i'll answer hoping it helps:

A RAW file is a file (!!!) I mean it is not an image but a data file. I contains
data regarding what every single pixel has recorded (light related) and which
place or position is the pixel data relate to in the whole record.

Upon conversion in any other format (this will necessarily be an image file),
a colour space will attributed and the three channel if in tiff or colour codes
if in jpeg (and compression applied). In tiff, this three channel colour infor-
mation is responsible for the bigger size expressed in MB. Add to this the
chosen ppi and now one may speak of "huge size" image if you converted
at 100%… not so huge if you applied a reduction (<100%).

[ajohnw]

Thanks Kodiak. My confusion is that it seems that the ppi setting doesn't make any difference to the size of the tiff. I do see that the raw file is just a data file --> debayering ---> some format. So that why I assumed something like a 20mp raw will produce a tiff of around 100mb.

John
-

[dje]

Hi Neil

Dan's summary above covers the situation pretty well I think. It sounds like you are doing something wrong to get such small jpegs when using the maximum quality setting (even with the square crop). There is no mathematical formulae to calculate the size of the final jpeg - it very much depends on image content.

My guess is that you might be fiddling with the document size settings under the Image Size screen in PS (changing document size and resolution). If this is the case, my advice is to leave this as it comes up and just run with the pixel dimensions as per the original image (changing document size settings will change the pixel dimension).

Dave

[ajohnw]

Thanks Dan. That is exactly how I thought it worked but have seen some crazy dpi figures in some images so some might think it makes a difference.

John
-

[pnodrog]

Hi everyone!

My clients require 2MB jpegs @ 300dpi for print. Seems reasonable, right?

I shoot RAW and process as 16 bit Tiffs. After editing in Photoshop (cc2014) I end up with files around 350MB. However, when I save as Jpeg, I very often get files of 1.5MB which my clients reject. So I give them the Jpeg2000 format which is a longer process to complete.

Am I doing something wrong? Is there a mathematical equation to calculate the Tiff to Jpeg conversion?

Thanks for any clarification.

Neil.

Your clients are uninformed. The first thing needing consideration is the size of the final print will be. Another is the detail in the image, as large blocks of the same colour will compress far better than an image with fine detail all over it. It is likely that a 1MB jpeg file of large blocks will have good definition at the block boundaries where as a 2MB jpeg image with lots of detail could be unacceptably soft. Jpeg file size is not a good way of stipulating quality.

Printers should stipulate minimum pixel dimensions required for the print size. If you know the final print size you can use their DPI requirement to work it out. Next the printers should let you know the maximum jpeg compression acceptable. The resulting jpeg file size will then depend on the image content. The DPI value has no effect on the file size as it is just an entry in the metadata that subsequent software may or may not use.

All you can do is save as a jpeg with photoshop at quality of 11 - 12 or (95-100%) or offer to supply as Tiff.

P.S. You may like to look at this site http://fotoforensics.com/tutorial-estq.php

[loosecanon]

err Are not jpegs 8 bit files - so converting from 16 bit tiff to jpeg loses a lot of colour info, compression will lead to loss of detail, how significant only yo can tell.

[irlien]

Thanks for your input everyone.

I haven't changed document size anywhere in my process, except for cropping where I simply choose the 1x1 format.

I do believe the client is misinformed. They are getting their instructions from a PR company specialised in the distribution of photos to journalists. Their site, at least the part I can access, stipulates the photos should be at least 1,000 pixels on the longest size. Photos will be printed in A4 glossy magazines.

I chanced upon fotoforensics while researching this issue, I must give it a proper read again.

I'm still surprised by the size of my Save As Jpegs all the same. Could it be because they are very fine pieces of jewellery on white backgrounds, i.e. with little information in the file? Still, one particular Tiff measures 84MB and saves as a 1.8MB Jpeg.

[dje]

Neil

I realize you might have commercial reasons for not posting a sample but it might help if you could give us a link to one of the "problem" tiffs. (It would be too big to post directly to this website). There are plenty of file hosting sites around such as Google +, Dropbox etc.

Dave

[george013]

err Are not jpegs 8 bit files - so converting from 16 bit tiff to jpeg loses a lot of colour info, compression will lead to loss of detail, how significant only yo can tell.

Converting from 8 to 16 bit causes no loses of colourinfo. A typical gray in 8 bits could be 64,64,64. In 16 bits that would be 16384,16384,16384. For both you could write 25%,25%,25%.
George

[george013]

Thanks for your input everyone.

I haven't changed document size anywhere in my process, except for cropping where I simply choose the 1x1 format.

I do believe the client is misinformed. They are getting their instructions from a PR company specialised in the distribution of photos to journalists. Their site, at least the part I can access, stipulates the photos should be at least 1,000 pixels on the longest size. Photos will be printed in A4 glossy magazines.

I chanced upon fotoforensics while researching this issue, I must give it a proper read again.

I'm still surprised by the size of my Save As Jpegs all the same. Could it be because they are very fine pieces of jewellery on white backgrounds, i.e. with little information in the file? Still, one particular Tiff measures 84MB and saves as a 1.8MB Jpeg.

If they are printed full size on a A4 and the longest site should be minimal 1000pixels, then they are printing on 1000/12=84 DPI.

George