Preferred technique for downsizing a photo? (Page 2): OK if you're looking at the full image. But if you're expanding the image beyond the screen (which a judge MIGHT do in a...

DirtFarmer Loc: Escaped from the NYC area, back to MA

SuperflyTNT wrote:

Actually until the resolution is the same width in pixels as the display device you’re better off reducing image size. Any resolution greater than the display you won’t see so level of compression will have more of an effect on IQ. Refer back to Paul’s post on resizing images. Follow those instructions.

OK if you're looking at the full image. But if you're expanding the image beyond the screen (which a judge MIGHT do in a competition) I think the resolution should be kept as high as possible. After all, you don't know how the judges are judging, nor what kind of screen they're using.

TomHackett Loc: Kingston, New York

BigDaddy wrote:

If the image size if 2736x3648 then I'd bet the jpg file size way under the 5mb limit?

Using Photoshop's Save for Web (Legacy) function, I was able to get below the 5mb limit by either setting the Quality (governs JPEG compression) to 83 (out of 100) or the Percent (number of pixels) to 76. Using the "blink test," I decided that the JPEG compression was just a bit sharper than the image size (number of pixels) reduction. It was difficult, really, to tell the difference.

TomHackett Loc: Kingston, New York

BigDaddy wrote:

It's a good question if compression or downsizing the photo effects quality the most.

Yep. That was the original intent of this topic.

Thomas902 Loc: Washington DC

"...(I'm not resaving JPEG files; I'm always starting from the original CR2 file.)... Wise, jpg is NOT the way to go for any serious (or commercial work albeit wedding shooters can (and do) use .jpg which for Nikon shooters allows them to tweak "Picture Controls" to obtimze for their particular visual statement.)

"...Save for Web is a great option..." this is so wrong, but I'm not going to go into why... Research this TomHackett, it's primarily for those who are naive, lazy or don't understand how to "Convert to Profile".

Gene51 touched on an important point (Maximum Pixel dimension) giving the Facebook Max of 2048. In fact Nikon's Facebook page typically uses this 2048 on longest side for their post... I don't hang out on Canon's Facebook page but I'm guessing the follow suit here.

Ok, surprisingly no one has mentioned the most IMPORTANT aspect of downsizing an image for delivery to their client(s) be it commercial or a "juried show" That being the VERY LAST step in post before you save the "downsized" file is SHARPENING! Nothing wrecks havoc in IQ is that of downsizing an image that has already been "Sharpened" Don't make this mistake... Always make your final sharpening the very last step in your post workflow.

Question for you TomHackett... Does this "juried show" require a fee to enter? If so it is likely a scam, even if they are claiming to offer a "Prize" to the winner(s). I learned this early on in my photographic journey Tom... For "Placing" in a juried show put on by the Washington County Museum of Fine Arts I received a Silver Ribbon and a $25 discount from a local "Framing Shop" Really? Never again... once burned twice shy... from Aesop's fables.

Hope this helps TomHackett... btw, why don't you see if the local galleries in your market will display your photo-artistry? Albeit Galleries are notorious for taking 40% to 60% commission on each sale... That said if you price accordingly you may indeed generate revenue... My favorite? I display at a local "High End" chic eatery in my market... they actually only take a 15% commission... That works :)

All the best on your marketing efforts TomHacket... always wise to get your name out there in your market!

CHG_CANON Loc: the Windy City

TomHackett wrote:

Using Photoshop's Save for Web (Legacy) function, I was able to get below the 5mb limit by either setting the Quality (governs JPEG compression) to 83 (out of 100) or the Percent (number of pixels) to 76. Using the "blink test," I decided that the JPEG compression was just a bit sharper than the image size (number of pixels) reduction. It was difficult, really, to tell the difference.

And when you resized the pixel resolution to 2048px on the long size with 0% JPEG compression, what did you see? How large was the file?

TomHackett Loc: Kingston, New York

BigDaddy wrote:

If the contest is judging via digital display, I'd want to know the display size and would size my photo to those dimensions, or that aspect ratio for sure.

Well, good luck getting that information from the juror(s)! As far as aspect ratio is concerned, I determine that at crop time, based on my composition decisions. As an extreme example, I'm not going to adjust the aspect ratio of a photograph in portrait orientation to fit anyone's landscape mode display.

BigDaddy Loc: Pittsburgh, PA

TomHackett wrote:

Using Photoshop's Save for Web (Legacy) function, I was able to get below the 5mb limit by either setting the Quality (governs JPEG compression) to 83 (out of 100) or the Percent (number of pixels) to 76. Using the "blink test," I decided that the JPEG compression was just a bit sharper than the image size (number of pixels) reduction. It was difficult, really, to tell the difference.

I dunno about PS save for web option. It used to mean use only web safe colors, which you sure don't want for a contest. Not sure if it still means that or not, but I never used it, and I was a web developer for many years.

DirtFarmer Loc: Escaped from the NYC area, back to MA

TomHackett wrote:

Using Photoshop's Save for Web (Legacy) function, I was able to get below the 5mb limit by either setting the Quality (governs JPEG compression) to 83 (out of 100) or the Percent (number of pixels) to 76. Using the "blink test," I decided that the JPEG compression was just a bit sharper than the image size (number of pixels) reduction. It was difficult, really, to tell the difference.

Glad to hear you found a use for the blink test.

CHG_CANON Loc: the Windy City

Why waste time in PS when the LR Export process is dedicated to this entire question.

TomHackett Loc: Kingston, New York

BigDaddy wrote:

I dunno about PS save for web option. It used to mean use only web safe colors, which you sure don't want for a contest. Not sure if it still means that or not, but I never used it, and I was a web developer for many years.

I guess I need to recant, rephrase or rethink Save for Web. It just seemed like a convenient tool for comparing downsampling and compression. As I noted earlier, it does not support the latest algorithms. I don't know about web safe colors--it doesn't actually mention that. Export as. . . is probably a better option.

DirtFarmer Loc: Escaped from the NYC area, back to MA

CHG_CANON wrote:

Why waste time in PS when the LR Export process is dedicated to this entire question.

You can probably do a form of blink test in LR to compare photos. LR allows you to expand the image so you are looking at a limited area. If you do that in Loupe view, then switch back and forth between two images you can do a blink test. The only problem is aligning the two images so that switching doesn't introduce motion which would make comparison more difficult.

To compare jpgs that have been compressed you would still have to export the image, then re-import it so you could compare it. Of course you have to do that in PS also to get the jpg compression.

imagemeister Loc: mid east Florida

TomHackett wrote:

I have a CR2 file (Canon raw format) that is 2736x... (show quote)

I would NOT vary JPEG compression to get to size ! This WILL affect/damage fidelity tho however small it may be ! ......I WOULD - in your case - use the Adobe default "Bicubic Sharper" to reduce the file size from 10 MB to around 7.5MB by using trial and error on the long side dimension and then in another step reduce the 7.5 file down to the required 5MB. Going in steps reduces the potential for any " fidelity damage".
.

TomHackett Loc: Kingston, New York

CHG_CANON wrote:

Why waste time in PS when the LR Export process is dedicated to this entire question.

It's the same question either way. LR Export allows me to separately control the image size and the file size when converting to JPEG. But I'm still having to make the decision as to how much of each to use.

CHG_CANON Loc: the Windy City

TomHackett wrote:

It's the same question either way. LR Export allows me to separately control the image size and the file size when converting to JPEG. But I'm still having to make the decision as to how much of each to use.

And when you resized the pixel resolution to 2048px on the long side with 0% JPEG compression, what did you see? How large was the file?

SuperflyTNT Loc: Manassas VA

DirtFarmer wrote:

OK if you're looking at the full image. But if you're expanding the image beyond the screen (which a judge MIGHT do in a competition) I think the resolution should be kept as high as possible. After all, you don't know how the judges are judging, nor what kind of screen they're using.

Most judges don’t pixel peep and if they do they wouldn’t go beyond 1:1. Actually most competitions restrict the size. For our club the software for uploading restricts the size and if you submit an image larger than specified automatically downsizes it.