Output Settings for Automate PDF Presentation

[PWeareB]

Hello All:

I am creating a multi-page pdf document using Photoshop CC 2019 with the feature "Automate, PDF." My PDF will contain only images, such as a portfolio.

While it is fairly easy for me to create, I notice that once I open the pdf with Acrobat or Reader, the images do not look sharp, they look a bit "jaggy," even though they looked spot-on in Photoshop when I was creating the PDF.

Does anyone have tips for the settings, or some other feature, when I create the pdf that may be creating this problem?

Thanks.

PatrickB

[Conrad_C]

After you enter the filename and destination folder, the Save Adobe PDF dialog appears. In the Compression panel there, you can specify the downsampling resolution and the compression quality. If the current settings are too low-resolution for the display on which the PDF presentation will be viewed, you'll want to adjust them upward.

[PWeareB]

Thanks for the reply Conrad.

I chose "Do Not Downsample" because I wanted to keep the pictures at the size I made them in PS: 500 x 500 pixels at 72 dpi.  Would that make a difference?  However, I left the jpeg compression setting at maximum.

What about the "Adobe PDF Preset"?  I tried a couple different ones and no change.

Thanks.
PatrickB

[Conrad_C]

If the "For images above" value remains set to 450 ppi (or anything above 72 ppi), the 72 ppi photos aren't going to get downsampled because they are below that downsampling threshold value.

When the photos look jaggy or unsharp in Acrobat or Reader, is their size on the screen larger than it was in Photoshop? For example, if you open the PDF presentation in Acrobat, is it presented full screen? Because if the document page is shown larger in Acrobat or Reader than it is in Photoshop, the images will have a lower apparent resolution as the same number of pixels are stretched across a larger area. And 500 x 500 pixels is considered very low resolution to start with. So that's the next question: Is it possible that the images have too few pixels for the expected display size of the presentation?

What are the pixel dimensions of the screen are you targeting for showing this PDF presentation? For example, if you wanted to show a presentation on a 4K TV at the full resolution of that display, the page size should be 3840 x 2160 pixels, and any images to be shown full screen should meet those dimensions too. If a 500 x 500 pixel image was added to that presentation, it would only appear equal to the screen resolution if it was limited to 500 pixels or less along one side. If a 500 x 500 pixel image was scaled to the full height of a 1080 HD or 4K screen, in both cases it would look jaggy because 500 pixels is less than half as tall as a 1080HD screen, and less than 1/4 as tall as a 2160 4K screen.

[PWeareB]

Conrad,

Yes, they do in fact look larger in Acrobat than in PS, and the view mode is 100% in Acrobat. I had thought that if I wanted the pictures to be seen in the PDF at a certain size, such as 5x5 inches, then that is the size I should resize them to in PS. From what you are saying this is not necessarily going to happen.

And, I simply want to be able to email the PDF for someone to view on a computer monitor, so I don't know what the final display will be.

Is the only way to control that is to leave the images at their original size and then check the downsampling option for the size I want them to appear?

Thanks again.

PatrickB

[Conrad_C]

Yes, that's right, displaying at exactly 5x5 inches is not necessarily going to happen, because we can't predict which screen size someone will open it on. They might open it on a 9.7-inch diagonal iPad, or a 27-inch diagonal desktop display. That means it's not worth your time to fit it to different displays; instead, just make sure there’s enough quality for most viewing conditions.

PWeareB wrote: “Is the only way to control that is to leave the images at their original size and then check the downsampling option for the size I want them to appear?”

It isn’t the only way, but it’s probably the way that’s the least amount of work. Load the images into Photoshop at their original resolutions, and let Save Adobe PDF downsample them. But what number to enter?

Probably not 72 ppi. Almost all desktop, laptop, tablet, and phone displays today are well over 100 ppi, especially Retina (Mac) and HiDPI (Windows) displays which can exceed 200 or even 300 ppi. For an on-screen presentation, entering 150-200 ppi should result in a good middle ground of acceptable sharpness on most devices. (300 ppi is more likely to be used when a PDF is expected to be printed on a high-quality printer, or if you want recipients to be able to zoom in on the photos to see maximum detail.)

Maybe run a test with:

• Images brought into PDF Presentation at original resolution
• Bicubic Downsampling To set to 150 ppi
• For Images Above set to 200 ppi
• JPEG compression set to High

Then, take the resulting PDF and:

• Test it on as many screen sizes as you have access to. If the photo quality is not good enough, try more tests that increase the downsampling resolution, the compression quality, or both.
• Look at the file size. If it's too big, consider reducing the downsampling resolution, the compression quality, or both.

You can tell from those two points that you will need to balance photo quality with file size, because you’re going to be emailing this presentation, and file size affects the time to upload and for your recipients to download. The more photos used in the presentation, the more challenging that balance might be. Note that some email services limit the size of attachments that can be sent or received. If you find that the settings that best preserve photo quality produce a PDF file so large that it might be blocked as an email attachment, consider uploading it to cloud storage such as Dropbox or Creative Cloud Files, and send your recipients a download link to it instead.

[PWeareB]

Hello Conrad,

Thank you so much for all this really helpful advice!

Much appreciated.

PatrickB