Join Deke McClelland for an in-depth discussion in this video Upsampling vs. real pixels, part of Photoshop CS6 One-on-One: Fundamentals.
In this movie, I'll show you the difference between manufacturing pixels by upsampling in Photoshop versus capturing a high resolution high-quality image in the first place with your scanner or digital camera. I'm still working in that duplicate version of the low res image. I'm going to go up to the Image menu, and choose the Image Size command. I'll make sure that Resample Image is turned on, Constrain Proportion should be turned on as well. The Scale Styles option only matters for layer effects and we don't have any layers inside this image, so it doesn't matter.
Just make sure those final two check boxes are turned on, and then, let's go ahead and send that Resolution value through the roof. I'm going to crank this up to 1000 pixels per inch, which is way more than I need for printing purposes but great for demonstration, and then I'll go ahead and click OK. Now I'm still viewing the image at the 100% view size. However, I'm looking at some detail in the center of the image. So I'll press and hold the H key, click and hold, then drag up to the eyes of this Tyrannosaurus over here in the right-hand side, and release. You can see that we have some pretty gummy detail, but you might argue it's better than the original.
I'll go ahead and switch back to that original low resolution image. I'll drop down to this little zoom value here, and change it to 1000% so that we're equally zoom in on the image. So I'll go ahead and press and hold the H key, click and hold inside the image, drag over to the dinosaur's eyes, and release. Now because we're zoomed in farther than 600%, we can see the pixel grid, which are the lines between the individual pixels. The easiest way to hide those lines is to press Ctrl+H or Command+H on a Mac. And that way, we'll just be able to focus in on these pixels.
Now obviously, we have some pretty choppy transitions inside this low res image, whereas inside the upsampled version of the image, the transitions are a heck of a lot smoother as you can see. So we don't have that appearance of jagged edges. Of course, we can't see the individual squares as we can in a low res image. Even so, I wouldn't say that we have a particularly detailed graphic, whereas, let's take a look at a high res version of this image created by scanning the image at a high resolution in the first place. Notice I'm viewing the image at the 10% zoom ratio, so I am way zoomed out from this image at the moment.
I'm going to press Ctrl+1 or Command+1 on the Mac to zoom all the way in, and then I'm going to once again press and hold the H key, and drag over to the T-Rex's eyes like so, and notice the gorgeous detail inside this image. You can see the independent crayon lines, you can see all this edge detail associated with the water coloring, you can even see the paper texture. Compare that with the upsampled version of the file and you can see that real pixels captured with a scanner or digital camera just can't be beat, because the fact of the matter is when you upsample an image, Photoshop just has the original pixels to work from, and it can't make up new detail.
I want you to notice one more thing about these images. If I switch back to the zoomed in low res version of the graphic, you can see down here in the lower-left corner of the window that the document size is 1.66 Megs. If you can't see that value by the way, click on the right-pointing arrowhead and choose the Document Sizes option. That's a very small file in memory. Photoshop can easily handle files of this size with no delay whatsoever. Whereas, these other two files, both the upsampled version of the image, and the scanned high res version of the image are right at 166 megabytes in memory.
What that means is that you are going to have occasional delays while editing such files, especially as you add layers to them. As a rule of thumb, it depends on your system of course, but that performance threshold occurs around 100 megabytes, just so you know. But even now these two files are exactly the same size, and require the same performance hit where Photoshop is concerned, this file which has the same Resolution value of 1000 pixels per inch, does not contain nearly as much detail and this is a function of what's known as Spatial Resolution, which is how our eyes resolve the detail.
So this upsampled version of the image is said to have a low spatial resolution, where the high resolution scan is said to have a high spatial resolution, and that's what you want. So when in doubt, scan as many pixels as possible. You always want to go with the highest optical resolution that your scanner offers. And where your digital camera is concerned, you always want to capture at its maximum resolution as well, because what you want in your digital images regardless of where they're ultimately going, print or web, is as much detail as you can get.
- Opening an image from Photoshop, Bridge, or Camera Raw
- Navigating, zooming, panning, and rotating the canvas
- Adding, deleting, and merging layers
- Saving your progress and understanding file formats
- Cropping and straightening
- Adjusting brightness and contrast
- Identifying and correcting a color cast
- Making and editing selections
- Enhancing portraits by retouching skin, teeth, and eyes
Skill Level Beginner
Q: Where can I learn more about graphic design?
A: Discover more on this topic by visiting graphic design on lynda.com.
Q: When I double click the welcome.psd file included with the exercise files, I get the following error message:
"Some text layers contain fonts that are missing. These layers will need to have the missing fonts replaced before they can be used for vector based output."
Unlike the TIF and JPEG files which display and open correctly, all the icons for PSD files are blank but other than the welcome.psd file, they seem to open correctly without the error message. Is this a problem that I should address (perhaps re-download the files or find the missing fonts)?
A: The TIFF and JPEG files are flat, so they don't contain fonts and the operating system can interpret them (and generate thumbnails) without help from Photoshop. The PSD files have two issues:
First, they may contain editable text complete with font info. The files are designed with fonts that ship with Photoshop, so you don't get error messages, but Adobe sells some versions of Photoshop without fonts. This may be your issue.
Second, the PSD files contain no flat previews. This makes for smaller files, but it means the operating system, Mac or Windows, cannot generate previews. That won't effect your experience in Photoshop, but it does mean you can't see the file until you open it.
Photoshop CS6 One-on-One: Intermediatewith Deke McClelland9h 25m Intermediate
1. Opening an Image
2. Getting Around
3. Image Size and Resolution
Digital imaging fundamentals1m 45s
The Image Size command3m 27s
Common resolution standards3m 20s
Upsampling vs. real pixels4m 36s
Changing the print size6m 16s
Downsampling for print4m 12s
Downsampling for email3m 11s
The interpolation settings5m 22s
Downsampling advice4m 36s
Upsampling advice6m 10s
4. Using Layers
5. Saving Your Progress
6. Crop and Straighten
7. Adjusting Luminance
8. Adjusting Colors
9. Select and Edit
10. Retouch and Heal
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