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stonemason

Widescreen and .jpg size

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Now that slideshows are being made in widescreen format, 1920 x 1080 or 1920 x 1200, with the intention of maximising quality, I thought it may be a good time to ask the more experianced users to express their thoughts on what they consider a good trade off in quality against jpg comression. In the past I have always used the maximum jpg size (12). However this is now leading to bigger and bigger file sizes, and bigger load on the equipment when using animation. Any thoughts on this would be appreciated.

Geoff

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Quality '12' was in any case way too much ! Keep to 7-8 and everything will be fine and smooth, with smaller files and no visible quality difference.

It's very easy for you to see: make a short slideshow composed of the same picture with different compression ratios and run it. As soon as you really see a difference, choose the better compression ratio one step before (or after, depending on the way you organise the slides!)

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Following what I said above, here's a little test-game produced by my friend Aginum. In the attached slideshow, there are 6 identical slides, size 1800x1200 px.

They come from an original jpeg picture at 5616x3744 px. One of these is the original put straight into PTE, without prior downsizing. The 5 other have been reduced in Photoshop at 1800x1200 px with compression ratios ranging from 100/100 to 30/100 (values of "Save for the Web" function). The resulting image file weights are: 12.8 MB, 1,5 MB, 270 KB, 194 KB, 152 KB and 125 KB.

Of course, the images are not shown in a logical order - it wouldn't be fun ! as the game is to find the 'quality' (or compression ratio) in decreasing order. Change of image is done with keyboard or mouse action, so that you can stay as long as you wish on the images to study them.

Here's the test exe file.

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Guest Yachtsman1

Hi Geoff

I've just started using 16-9 & have been sizing my images to 1920x1080 pixels, quality 5 in Elements 10, & "Good Compression Ratio 30 in Nikon NX2, this has kept my file sizes down on the shows I've converted, the biggest with 120 slides was about 40MB, the one today with 70 slides, 28MB. IMO you only need to have medium quality as PTE makes them as good as you can get, on a big zoom or pan I up the image size to prevent pixillation, the sharpening adjustment in 7 seems to help dodgy movement..

Regards Eric

Yachtsman1

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Geoff,

If you use "Save for the Web" (two up and 100%) you can see the point at which the jpeg artifacts will begin to show before pressing save.

It will not be the same value for all images but you will get a feel for what suits your PP style after a short time.

It will vary by camera so putting a hard figure on it is not a good idea.

I have no wish to offend anyone or upset but 1920*1200 is dead. I have one but will not get another.

DG

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Geoff

Since being a user of a large flat screen, I found that sometimes, maybe on blue skies saving a Jpeg at level 6, which was always OK for CRT monitors is just a bit low. If a fair bit of editing has been done to a sky for example, I think level 6 can sometimes show that up too, so I now standardardise on level 8. On many images you may not notice the difference, but you always seem to see it when your showing the show to others and then its rather annoying.

Eric

Be carefull, your doing a lot of work making your shows widescreen and saving at level 5 is something I would not do. I thinks its just a bit too low.

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Just to add a note on the side: if you use Photoshop CS (not Elements), it's better to use the function 'Save for the Web' which offers several additional options, can suppress all or some exif data (thus making the file a bit lighter) and uses a 100% quality scale instead of 12-base, which is often easier to understand and makes the comparison easier with other softwares as far as compression is concerned.

And don't forget to run the test file attached above and to give your estimates about the visual quality ranking of the 6 slides !

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Guest Yachtsman1

Geoff

Since being a user of a large flat screen, I found that sometimes, maybe on blue skies saving a Jpeg at level 6, which was always OK for CRT monitors is just a bit low. If a fair bit of editing has been done to a sky for example, I think level 6 can sometimes show that up too, so I now standardardise on level 8. On many images you may not notice the difference, but you always seem to see it when your showing the show to others and then its rather annoying.

Eric

Be carefull, your doing a lot of work making your shows widescreen and saving at level 5 is something I would not do. I thinks its just a bit too low.

Hi Barry

I hear what you say but it's a balancing act, what I do is working for me & what I use my shows for, maybe it wouldn't float your boat? I've attached one of the pictures from todays Ripon cathedral show, saved at 5 in Elements, or good compression (30) in NX2 which I think is similar, can't remember which, with sky. What do you think.

Regards Eric

Yachtsman1.

post-5560-0-50464600-1330557457_thumb.jp

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Eric

Its not all images that I have noticed this with, so you may be OK with what your aiming for. Its was just the thought that a couple of years ago I would have said level 6 met all my needs, but since large widescreen use I have to add a but to that statement.

If your updating loads of older slide shows it would be a pain if you noticed a problem a little too late and as I recall you don't do heaps of animation so a level above 5 is not likely to affect what your doing and how it plays. I just thought better safe than sorry

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It depends on what I'm going to do with any given image as to what Jpeg compression I choose. If the image is non-animated, I'll save at 8 but if there is animation involved, I choose 10. Most of my clients like to watch their shows on large TV's, thus the higher quality setting. The only down side of coarse, is the final file size but I'm OK with that.

Aspect ratio for non-animated image is 1920x1080 however, for zoomed animated images, I may go as high as 3840x2160 to ensure that I don't go past 100% at either end of the zoom.

PS It's nice that Eric has moved past the 20MB limit - good on ya!

Greg

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Thanks for all the replies,it's always good to keep in touch with what others are doing. After reading what eveyone has said and doing some tests myself, I think that I will make level 8 my standard. I don't use photoshop very much these days, as I find that lightroom suits most of my output needs (I always shoot in Raw)so "save for web" doesn't enter my workflow. If you have yet to try lightroom, I strongly recommend it especially the ability to create quick collections to begin the slideshow creating process.

Geoff

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Lightroom?

What's a Lightroom?:rolleyes:

I'm a Nikon user and therefore I have my own workflow which I am trying desperately to make Adobe free.

The point that I and a few others have made is that is easy, with "Save for the Web" to actually SEE any artifacts before pressing the Save button rather than Save, find a problem and have to go back again.

You should be OK with quality 8. The "boss" advises it. He used to be a 6 man but he is now an 8 man.;)

I'm a 12 man.

DG

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Following what I said above, here's a little test-game produced by my friend Aginum. In the attached slideshow, there are 6 identical slides, size 1800x1200 px.

They come from an original jpeg picture at 5616x3744 px. One of these is the original put straight into PTE, without prior downsizing. The 5 other have been reduced in Photoshop at 1800x1200 px with compression ratios ranging from 100/100 to 30/100 (values of "Save for the Web" function). The resulting image file weights are: 12.8 MB, 1,5 MB, 270 KB, 194 KB, 152 KB and 125 KB.

Of course, the images are not shown in a logical order - it wouldn't be fun ! as the game is to find the 'quality' (or compression ratio) in decreasing order. Change of image is done with keyboard or mouse action, so that you can stay as long as you wish on the images to study them.

Here's the test exe file.

Gérard,

I went thru the 6 images a couple of times and on my 24 inch computer screen I could not see a difference. If I had to pick the one that was not reduced I would say number 3.

Maybe if I saw them on my 42 Inch LCD TV, it would be different. I make my jpeg's for PTE from my Tiff images with "FastStone Photo Resizer" on setting 80.

Bert

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Geoff,

If you use "Save for the Web" (two up and 100%) you can see the point at which the jpeg artifacts will begin to show before pressing save.

It will not be the same value for all images but you will get a feel for what suits your PP style after a short time.

It will vary by camera so putting a hard figure on it is not a good idea.

I have no wish to offend anyone or upset but 1920*1200 is dead. I have one but will not get another.

DG

======================================

Greetings Davegee and all,

I have a question about the Photoshop's results using Save For The Web.

I took an original jpg image which was 8029kb. I resized it to 1920 on the long side at 100 quality. Its new size was 1855kb.

I then saved this file in several different programs with Quality at 80:

In Photoshop, its size became 447kb.

In IrFanView, its size became 433kb.

In FastStone, its size became 429kb.

However, in Photoshop, SaveForWeb, with Quality 80, its size became 939kb.

So my question is, why is Photoshop's SaveForWeb's result is so much larger than the other programs, with the same Quality 80 setting?

Gary

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Gary,

I think you have assumed that, in this context, Quality = File Size. File Size is measured in KB. What is the unit of measure of Quality? What does 80% Quality mean? For that matter, what does 100% Quality mean? To compare the Quality settings of two or more software products, without knowing the algorithms that they are using, is like comparing apples, to oranges, to bananas.

The only things that matter are: are you happy with the visual quality of the resulting file? are you happy with the size of the resulting file?

Everything else becomes academic.

Peter

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Hi Gary,

I think that this is going off at a tangent to the OP and if you want to pursue it maybe you could start another thread?

But in reply I would say that my reasons for suggesting Save For The Web (SFTW) were that it allows a preview of the quality of the resulting JPEG and any artifacts would be visible before the Save button is pressed.

Does Irfanview or the other one allow this?

Also I find the description of what you did a little "fuzzy" in the middle and don't quite understand your methodology. Could you not start with the Original Full Size JPEG in each case (each software)?

Here is what I would expect in CS4:

My RAW Image when sent to CS4 would open up as a 75Mb 16Bit 4832 wide TIFF.

I would resize (using the crop tool) to 1920x1080.

I would select File> SFTW.

With "Convert to sRGB" ticked; Metadata=None; JPEG Quality = 100 the file size is 1Mb.

At JPEG Quality = 80 the output file size is 464Kb.

At JPEG Quality = 60 the output file size is 283Kb.

DG

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With "Convert to sRGB" ticked; Metadata=None; JPEG Quality = 100 the file size is 1Mb.

At JPEG Quality = 80 the output file size is 464Kb.

At JPEG Quality = 60 the output file size is 283Kb.

Thus demonstrating very clearly that, whatever the "measure" of Quality may be, it isn't file size! At Quality=80 the file size is 45.3% of the Quality 100 file; and at Quality=60 the file size is 27.6% of the Quality 100 file. (464/1024*100 and 283/1024*100 respectively)

Peter

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Hi Gary,

I think that this is going off at a tangent to the OP and if you want to pursue it maybe you could start another thread?...

DG

============================================

Davegee,

I don't see that this is 'off at a tangent'. I think it is exactly what the original posting is all about, which was about reducing the size of files but keeping sufficient quality. He mentioned specially widescreen format (1920x1080) and Quality size of '12'. And you mentioned Save for the Web (SFTW). Also, using Quality setting of 80, seems to be mentioned as a good starting point.

Given all of this, all I did was resize an original image to 1920 on-the-long-side and see what the results would be by reducing the file size using '80' using different programs. They all came close and I understand each one has a different algorithms which gives slightly different results. That was not my point.

My point was that just choosing '80' with SFTW will not give you anything close to what other programs would give you. Yes, you are right that other programs do not let you Preview the results, but when the file size is double the size of the other programs, I don't see that as a real advantage. The point was to get the file size down to a reasonable size with acceptable quality. I can view the results individually later.

I put each of the images I created in my test, along with the original full size image, into PTE and I could not see the difference at all between them. I viewed them on my PC and I viewed them on my 40" Samsung flat screen. I could not see any difference between any of them. I also threw in an additional image that was reduced to 1000x633 at 80 with a file size of 147kb. Still, I could not see any difference between it and the original file.

I don't see why you see my description to be 'fuzzy'. I think we did the same thing. My SFTW file is about half of the original, as was yours. The only difference is that I reduced my original image using 1920 on-the-long-side which gives me 1920x 1272, as opposed to yours which was 1920x1080, giving you a slightly less than half the size.

So, perhaps, if we used, say, '60' or '50' in SFTW to get an reduced file size comparable to what others programs would give, we would get the file size down and retain the same quality. I have not had a chance to try this. But my only point was that '80' in most other programs do not produce a comparable file size that '80' would produce in SFTW.

Gary

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Gary,

I think you have assumed that, in this context, Quality = File Size. File Size is measured in KB. What is the unit of measure of Quality? What does 80% Quality mean? For that matter, what does 100% Quality mean? To compare the Quality settings of two or more software products, without knowing the algorithms that they are using, is like comparing apples, to oranges, to bananas.

The only things that matter are: are you happy with the visual quality of the resulting file? are you happy with the size of the resulting file?

Everything else becomes academic.

Peter

====================

Peter,

No, I am not assuming that Quality = File Size. But one might expect that a Quality setting of '80' would give comparable (not exact) results in different programs (understanding that the algorithms would not be exactly the same). However, the Quality setting of '80' does not give similar results when using Save for the Web. See my response to Davegee. In my test, it was about double the size as other programs. To me, that is significant.

Gary

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Hi Gary,

Here's the bit that I found a little "fuzzy":

"I resized it to 1920 on the long side at 100 quality."

I'm not sure where the 100 comes into it when resizing?

My figure for Quality 80 in SFTW = 463Kb

Your figure for Quality 80 in SFTW = 939Kb

Something not right?

You took a JPEG and resized it and then Saved it again as JPEG - you re-opened the second generation Saved JPEG in three different programmes and Saved again as JPEG.

I was suggesting that a better workflow would be to open the original in each of the three programmes and take them to the final cropped and re-sized JPEGs in one editing operation and avoid the intermediate Saves?

Best wishes,

DG

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Hi Gary,

Here's the bit that I found a little "fuzzy":

"I resized it to 1920 on the long side at 100 quality."

I'm not sure where the 100 comes into it when resizing?

My figure for Quality 80 in SFTW = 463Kb

Your figure for Quality 80 in SFTW = 939Kb

Something not right?

You took a JPEG and resized it and then Saved it again as JPEG - you re-opened the second generation Saved JPEG in three different programmes and Saved again as JPEG.

I was suggesting that a better workflow would be to open the original in each of the three programmes and take them to the final cropped and re-sized JPEGs in one editing operation and avoid the intermediate Saves?

Best wishes,

DG

=================================

Davegee,

Ok...I kinda see your point. I meant to say that I saved the resized image at 100%, or actually the '12' Quality setting when you do a 'Save As' in Photoshop. I was trying to say that I did not reduce the Quality at that point.

What puzzles me is that when you did the SFTW with quality setting at 80, your file went from 1Mb to 464kb (about half).

When I did the SFTW with the quality setting at 80, my file went from 1.8Mb to 939kb (about half).

When I did just a 'Save As' with the quality setting at 80, my file went from 1.8Mb to 447kb (about a quarter).

To get the file size down to a comparable size as the other programs, using SFTW, I had to set the Quality somewhere between 50 and 55. I don't think changing the workflow to do the resize and quality setting in one editing operation is going to make such a big difference in the file size. Sure, it is best not to do too many resaves with jpgs. But my point, again, is when you choose to do a SFTW in Photoshop, the 80 Quality setting does not give you a similar sized file reduction as you might expect, when compared to just doing a 'Save As' with the Quality setting at 80. I am just wondering why because I would expect the SFTW's results to actually be a smaller file size than just a 'Save As'. No?

And, when I put all of these SFTW versions, and compared them to the original 1920 resized image, I could not see any difference in quality when viewed in PTE

Gary

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Gary,

I used your figure of 1920x1272 and Quality 100 and could still not get above 1.2Mb (consistently).

The corresponding figure for quality 80 was 509Kb.

At this figure the artifacts due to compression are acceptable.

By the time I get down to 60-70 the artifacts due to compression are unacceptable (to me).

I remain a quality 100 man. I will use quality 80 if I am using jpegs sized at 3800 - 4800 pixels wide in PTE (but I don't then use SFTW).

DG

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Hi Davegee,

Gary,

I used your figure of 1920x1272 and Quality 100 and could still not get above 1.2Mb (consistently).

Not sure what you mean by this.

The corresponding figure for quality 80 was 509Kb.

If SFTW was used, this is roughly 50% of the original, and about what would be expected (from my tests)

At this figure the artifacts due to compression are acceptable.

By the time I get down to 60-70 the artifacts due to compression are unacceptable (to me).

I remain a quality 100 man. I will use quality 80 if I am using jpegs sized at 3800 - 4800 pixels wide in PTE (but I don't then use SFTW).

Yea, I don't use SFTW either....:rolleyes: File size results with SFTW are too large.

Gary

DG

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I used your figure of 1920x1272 and Quality 100 and could still not get above 1.2Mb (consistently).

Not sure what you mean by this.

I mean that I don't know how you got 1.8Mb? Edit - OK - I concede - I used a MUCH more detailed original and got that high!

By the time I get down to 60-70 the artifacts due to compression are unacceptable (to me).

I remain a quality 100 man. I will use quality 80 if I am using jpegs sized at 3800 - 4800 pixels wide in PTE (but I don't then use SFTW).

Yea, I don't use SFTW either....:rolleyes: File size results with SFTW are too large.

You misunderstand - SFTW would refuse to handle a file that big. Most of the time I am saving from NX2 at quality 100 for a 1920x1080 or 80 for a 3800 - 4800 pixel wide file (regardless of file size).

DG

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