How do I improve the image quality for online publishing? Photoshop/InDesign/Acrobat Pro

[terin1]

I am using Adobe InDesign v.16.2.1 and Photoshop v. 22.4.1 on a MacBook Pro, OS 10.14.6.

I have a large architectural rendering (36" x 48") that was hand-drawn and scanned at 300 dpi then retouched in Photoshop. From Photoshop, I saved the file as a jpg and as a pdf (so that I can see which works best). I then created a 36" x 48" artboard in InDesign, imported the jpg file at 100% to use as a base map, and added additional title block text and images overlaying the base map. The completed plan is saved as a jpg and as a pdf. 

I will include this rendering in a final printed document about the design. The document is an 8.5" x 11", double-sided booklet with the 36" x 48" plan included as a folded insert. Primarily, however, it will be available online as a pdf. The problem is the online version. I'd like it to read like a book, i.e., with 2-page spreads and a right-hand cover. This is easy to create in Adobe Acrobat (Pro). 

The first problem is that once placed in InDesign, the rendering looks pixelated and the hand lettering on the rendering is nearly impossible to read. I'm definitely not enlarging the image--it's going from 36" x 48" down to fit on a 17" x 11" spread-- and I've tried changing the display performance to high quality but that doesn't help. The actual and effective resolution of the image is the same, 300 dpi. I've tried placing a jpg and a pdf, they both look pixelated. In Photoshop these both look crisp and sharp even when zoomed into on-screen. In Adobe Acrobat, the rendering looks pixelated although the images placed on top of the rendering look sharp. The goal is that someone could zoom into the rendering to see the details, but the image quality just isn't there in InDesign or InDesign exported as a pdf. 

Attached are three screenshots of the rendering showing the difference in quality (all zoomed to 121%) in Photoshop (PSjpg_121%.png), InDesign (ID_121%.png), and Adobe Acrobat Pro DC (Acrobat Pro_121%.png).

My question is, how can I improve the on-screen image quality of renderings exported to pdf for my online audience? Please, be specific in your recommendations, e.g., give the specs behind the "right" way to export/place into InDesign from Photoshop.

Thank you

[Test Screen Name]

There are some thing to try. JPEG is for photos. It should NEVER be used for line drawings or text. So don't save as a JPEG. Perhaps a TIFF. Convert it to 1-bit (monochrome) to get the size down, if it looks ok, otherwise greyscale.

Really though this seems a virtually impossible task. This is not how architectural drawings get to online!

[c.pfaffenbichler]

»JPEG is for photos.«

And that should be the very last step (the final pdf export in a case like this); using jpg to damage images in intermediate steps along the way to the final product is just not advisable. 

[terin1]

I save the rendering as a jpg because it is a photo (scan) of a drawing that also includes text and color. I will try TIFF though, that could be a solution. I'm interested in your comment "This is not how architectural drawing get to online!" How exactly DO they get to be online please?

[J E L]

@terin1 I am not sure I understand why you are using InDesign as an intermediary step? You can add text and extend canvas size in Photoshop, then export to PDF and assemble whatever print specification you want. What am I missing?

[terin1]

@J E L, I'm using InDesign because we overlay the rendering with details about the project. Then I'm incorporating the renderings into a multi-page document. When people zoom into the pages online to look at the rendering, the rendering looks blurry even though it's reduced in size from the original.

[J E L]

@terin1 I understand. I am wondering if all that could be achieved to get the look you want with Acrobat though, especially if you are only using InDesign to add text boxes. There is a lot you can do in Acrobat nowadays. Just trying to save you a step more than anything. But, ultimately, I think the issue is with your original scanning settings as has been pointed out by others. Please let us know what you try and how things turn out!

[rob day]

The actual and effective resolution of the image is the same, 300 dpi.

If you scale an image it’s Actual and Effective resolution would not match—a 300ppi image scaled to 50% would have an Effective res of 600ppi.

Can you select the placed image and show a capture of your Link Info panel?

[terin1]

@rob day below is the link info panel for the rendering in InDesign

[rob day]

The original scan was made at 150ppi, not 300ppi, and you are scaling the scan down by 30.9%. Also the format of the placed scan is JPEG, so the original could have JPEG compression artifacts, and then on the export to PDF, additional compression artifacts could be added depending on how you set your Export>Compression tab.

If you want to maintain the original scan quality in the PDF, rescan and save the map in a lossless format —TIFF, or PSD and not JPEG, which bakes in compression artifacts. Place the .PSD directly in InDesign, and export with Downsampling turned off and JPEG quality set to Maximum:

[rob day]

Also, I think you are assuming setting the Photoshop, InDesign, and Acrobat Zoom views to the same 121% will give matching views, but InDesign and Acrobat use a different view magnification scale than Photoshop—InDesign’s 100% view is the print output or Actual Size, while Photoshop’s 100% is a 1:1 image to display pixel ratio. And, you have also scaled down the art in InDesign.

To get a matching view you can set Photoshop’s and InDesign’s view to Actual Size, but then you would have to adjust the InDesign view to account for your 30.9% scaling of the art, so ID’s view would have to be 323%:

[terin1]

@rob day Thanks for that insight, I hadn't considered that when making the screenshots. Ultimately I think that means I need to save larger files so that the final user/viewer will be able to zoom in to see the details and notes. One way I've done it in the past is to insert a full-size (48"x36" or 36" x 24") pdf into the final document pdf. This messes with the 2-pages-up spread orientation of the pdf but at least it's more legible.

[rob day]

Just watchout for the Export Compression Tab’s for images above setting. Your map’s Effective Resolution already exceeds the default 450ppi. Scanning at a higher resolution would increase the image’s Effective res, but you’ll need to either increase the for images above and/or the down sample resolution, or turn off down sampling in order to get a higher resolution in the PDF.

[terin1]

@rob day  This is super helpful. I'm going to try this now and see if there are improvements.

[Eugene Tyson]

I wrote an article here which might shed some light on the situation

https://creativepro.com/high-res-image-look-low-res/#:~:text=By%20default%2C%20InDesign%20is%20set,a....

Scanning - the way I was thought - was to Scan at the actual size and resolution required - resizing after the scan will cause issues. 

Architectural renderings or anything like line drawings (including text) should be scanned at 1200 ppi or higher. 

The quality in the PDF is controlled in the InDesign PDF Export options - what are your PDF settings?

To answer your question -  your scans need to be higher resolution and your output to PDF needs to be high resolution. 

Acrobat can also display differently - 121% zoom in Acrobat is not the same as 121% zoom in Photoshop.

If you change the view resolution then viewing at 100% is different. 

I'd highly recommend rescanning the documents at a higher resolution and outputting a higher resolution PDF.

[rob day]

I have a large architectural rendering (36" x 48") that was hand-drawn and scanned at 300 dpi then retouched in Photoshop. 

If the 48" x 36" art was scanned at 300ppi it would have a pixel dimension of 14,400 x 10,800 pixels. If that pixel dimension is reduced to fit a 17" x 11" spread, the long dimension’s Effective Resolution should be 847ppi (14,400/17 = 847.05)—more than enough to reslove the ink drawing in your capture.

When you export to PDF, the default Compression setting for print presets is to downsample images with Effective resolutions over 450ppi, as well as apply additional JPEG compression. It looks like that is happening in your AcrobatPro capture.

[terin1]

I'll check this!

[terin1]

Thank you all for your replies!! I'm trying some of the ideas now.