How can I fix thin, diagonal, and 2-pixel wide lines printing out as pixelated and jagged?

[coolmodernist]

I have an illustration I created using 3d computer model. It had to be rasterized. Some lines that are really thin, when printed, look jagged and pixelated. Lines are mostly one pixel or two pixels wide. When it's a single pixel, its color is black. If it's two pixel side, one pixel will be medum gray and the other, black. For one pixel wide lines, obviously, diagonal lines do step a bit. Is there any way to fix this with one or two quick moves? Or do I have to manually chage every line?

Also, is there a way to change any of the print settings so that ink kind of blends these super subtle differences? I am using Canon Imageprograf PRO-300 inkjet printer.

Please let me know if you have any helpful suggestions and pro recommendations? Thank you very much!!!

[Conrad_C · Accepted solution]

The best way to fix this is to re-rasterize it from the 3D software with enough pixels for print, at the dimensions and resolution required.

To print on a pro Canon inkjet printer, a resolution of 300 ppi is reasonable for enough detail, so then you want to specify the dimensions in inches. For example, if you want to print on a US Letter sheet with an image that’s 10 inches wide, then you want (10 inches * 300 ppi) or 3000 pixels on the long side. So go back to the 3D application and rasterize it with the long side at 3000 pixels long, and it should look good in print.

Compared to that, what is the length of the rasterized image in pixels, and what print size do you want in inches or cm?

If you want to start from the images you already have, then you will need to use some form of upscaling. Photoshop offers several upscaling options. But the results you get from that are never as good as having an image of the proper resolution rendered directly from the original 3D model.

[coolmodernist]

Hi, Conrad, Thank you for your response.

I get your point about re-exporting. That is not currenlty an available option. I did a lot of post work and Photoshop file had not been structured in an organized way to swap out the base image from a 3D model so easily. It will require a lot of rework.

As for the image, it is fairly large. It's like 14" wide at 600 dpi. About 140 MB file.

I tried to shrink the image size and resample it with an option with preserve details. Then, I applied a sharpen tool. This semes to have done the trick. It prints fairly well. It was by some dumb luck this happened riht now. I will have to test out a few other adjustment options to stress test all the images and make sure it all works.

A quick question. What od you mean by upscaling? What kind of command and process can I try out? Please let me know.

Thank you again for your response.

[Conrad_C · Accepted solution]

OK. It sounds like you’ve already got at least a partial solution going, that’s good.

As for the image, it is fairly large. It's like 14" wide at 600 dpi. About 140 MB file.

By @coolmodernist

If that’s the size at which you need to print it, and that’s also what the dimensions are in Image > Image Size, then it sounds like the current resolution should be enough for that print size. But the examples posted earlier look much lower resolution than that, so what were the pixel dimensions (height and width in pixels) of the image as it came out of the 3D application, before any resampling in Photoshop?

A quick question. What od you mean by upscaling? What kind of command and process can I try out? Please let me know.

By @coolmodernist

Upscaling is the same as “upsampling” where you’re increasing the number of pixels in an image. Fortunately, you’ve already started down that road because you used a Resample option (Preserve Details) in Image Size. For a challenging image, some would test Preserve Details and the Bicubic options to see which one looks the best, because the best solution is not always the same one depending on the image and whether you’re increasing or decreasing the number of pixels.

For many years, the Resample options in Image Size were the main ways to adjust the resolution of an image. Recently, Adobe has used AI to add more ways to increase resolution. They can sometimes be better than Image Size/Resample, and like the Resample options, each can have a different effect on fine details:

Super Zoom. Choose Filter > Neural Filters, enable Super Zoom, set Output menu to New Document.

Super Resolution. Super Resolution is available only in Adobe Camera Raw or Lightroom, so it can be used only on file formats compatible with that software. It is not available for the Camera Raw Filter applied to a layer in Photoshop.

If you’ve heard of non-Adobe upsampling/upscaling apps such as Topaz Gigapixel AI, that’s a similar thing: Attempting to improve how increased resolution looks by applying AI/machine learning. These new AI methods also need to be tested with line art/synthetic art to see which one works best, because I’m not sure how much each AI engine is trained to properly handle details in images that didn’t come out of a camera. They are typically marketed with examples of photographic real world scenes.

[coolmodernist]

Hi, Conrad, Thank you very much again for your helpful explanation. As you recommended, I will try out differnet options available in the Image Resample dialogue box. Also, good to know about AI, Super Zoom, and requirements for Camera Raw and Lightroom. I see a lot of YouTube posts on Camera Raw and Lightroom by professional photographers and photo editing. Good to hear about non-Adobe options as well. For now, resample with preserve details seems to have done the job so I will stay with this workflow and explore other options as needed later.

I did not keep track of what number I used for Reduce Noise setting under Resample with Preserve details so I will have to test that out. Also,  I had applied Sharpen command to the image after resampling but had not tested printing out after Resample but before Sharpen. I will have to test some settings there as wel.

Not to extend this much further but just one last follow-up question. For a rasterized line drawing like the ones I am working with, would Sharpen do anything here to improve the printouts? Just curous to hear about your take on this. Please let me know if you would like.

Thanks much again, Conrad.

(My apologies for a bunch of typos. I will have to improve on this.)