Using Threshold in QuarkXPress 2017 for image masking

Tue, Apr 11, 2017

Feature, How-to, QuarkXPress 2017

QuarkXPress 2017 introduces transparency blend modes as well as reintroducing image effects and adjustments. The combination is, in publishing terms, golden, provided that you remember that things should only be done in QuarkXPress when they make the most sense to do so. QX2017 is not attempting to replace Capture One, Affinty Photo, Adobe Photoshop or your other favourite RAW developer or editor.

That said, there are an awful lot of image management processes which ought to be done in layout, and doing them earlier in the process is a messy compromise which requires numerous round trips. The most obvious example is Output Sharpening: easy in QX2017, a tedious nightmare previously. However, it will be hard to show the power of output sharpening on screen, so let’s look at another, equally tedious, problem: image cutouts.

Now, we all know that you can cut an image out in QuarkXPress or competing, bundled, software, but we also know that this is a relatively rough-and-ready process. Alternatively, we can go to Photoshop, perhaps using OnOne or Vertus to assist us. We know we are going to spend a long time cutting out, and, if the requirement changes, or the client decides that they preferred one of the alternative images after all, we are going to have to do the whole thing again. And, with cutting out in Photoshop, there’s always the nightmare situation of a cutout which looks totally clean on screen, but prints yellow splodges with hard edges at production.

What if you could do the whole thing in one minute, without leaving QuarkXPress.

Cutout and Shadow in a minute

Ok, here is a problem image taken at the British Museum: 

This one is straight out of the camera, supplied as JPEG, and it’s Hercules (or Herakles) on the right that interests us. You couldn’t possibly use that image, marred as it is by bad exposure, bad colour temperature, and reflection on the glass.

First, let’s crop it and blow it out using Levels. You’ll notice that we’re setting the transparency mode to Multiply. We’ll come back to that in a moment.

A bit of colour balancing in the Highlights enables us to get rid of some yellow splodges which we will not want.

Next, let’s use Threshold to give us a good black mask, which we’ll invert with Invert. You’ll notice we’re setting this to Lighten as a transparency mode.

Our final piece of image adjustment is to use Threshold again with Gaussian Blur to give us the shadow. For this, we’ll go back to our original image with its adjustments as a basis. We’re going to set the transparency of the shadow to 50%, and give it a white background.

As you can see, adjustments and effects in QX2017 stack, non-destructively, executing the top one first, then the second, then the third. Additionally, we’ll distort the image to suit. We can keep playing with this as we develop the document. I’ll make sure that I expand the box the shadow is in, with its white background, to the size of all the other elements.

Finally we are ready to composite.

Here goes:

Now, this is not perfect, but we have spent a total of one minute on it, and, since everything is done non-destructively, we can now refine to suit our task. In most publications this image would be relatively small, perhaps a marginal illustration. We would want to take more time if it was a main featured image—but, in that case, we would probably also insist on starting with a much better original.

A couple of remarks.

First, the image logic is important here. At the back we have the shadow. On top of this, we have the mask we created with Threshold and Invert, set to Lighten. Its black areas have no impact on the area below, as black + Lighten = nothing. Its white areas entirely knock out the shadow, as white + Lighten = white. The top image is set to multiply. Anything x black = black, and image x white = the original image. The result is that the white areas of the original image become entirely transparent, allowing the bottom shadow to appear, but the imaged areas are opaque.

This might sound complicated, but once you’ve got it, you can do one of these a minute.

Second, the drop shadow is important. Although a cutout onto white was easy here, using levels, the cutout then either appears to float in the air, or else sit two-dimensionally on the paper. You need a shadow, and it cannot be the Dropped Shadow effect, which will reenforce the sense of a flat picture laid onto the page.

Final thoughts

To extract this much quality in terms of a cutout in Photoshop or other software would take you twenty minutes at least. If the client changed their mind, that would be another twenty minutes. You would also need to render the shadow as a separate image—not just a separate layer—in order to be able reposition the shadow so that it works with the layout. Of course, you could use this same technique in Photoshop, rather than doing a laborious manual cutout, but you are still faced with maintaining separate shadow images, and further annoying round-trips if the layout changes.

I’ve already ordered, and paid for, my upgrade to QX2017. It is an intense privilege to be one of the beta-testers. I’m awed by the possibilities that the new version brings. I thought it would be very hard to cap the 2016 seminal release. I guess I hadn’t reckoned with the ingenuity and tenacity of the folks at Quark…

This post was written by:

- who has written 4 posts on Planet Quark.

Martin Turner is the author of Desk Top Publishing with QuarkXPress 2016, and presenter on the 2017 video series Desk Top Publishing with QuarkXPress.

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