Pixiq

Fine Art Digital Printing Workflow

It's been a month since my last posting. I am product manager for Pixel Genius Photokit Sharpener 2.0 and have been burning the midnight oil completing the user's manual. We released the plugin last week to rave reviews. For those interested in learning more about this plugin I've included a link to our site: PK Sharpener 2.0

 Global Adjustments in Photoshop

In my last post I discussed Foundational Adjustments. Once these adjustments have been implemented it’s time to begin dealing with Photoshop adjustments that affect the entire image. Generally these adjustments are a Luminosity adjustment followed by a Color adjustment. If appropriate additional LHS Global adjustments can be implemented at this point.

Global Luminosity Adjustment

With a Global Luminosity adjustment layer a Black Point, a White Point and over all contrast and luminosity can be adjusted. It is important to note that setting a Black Point and/or a White Point is not always necessary. If you’re optimizing an image of gray trees in the fog, for instance, setting a Black Point would obviously destroy the subtle gray scale. I rarely set a White Point but I do use it on occasion when I have an image that has a very bright area that intersects the paper margin. In this situation setting a White Point that is 6 - 7% will visually separate the lightest areas of the image from the paper.

When making any Global adjustments it’s crucial that all elements of the image benefit from the effect. It areas of the image suffer than you must back off the effect and use a Regional solution later on to complete the adjustment.

Setting A Black / White Point

There are a myriad of techniques to set your Black / White Point. Most of them work quite well. The method I use is a little more time intensive than others but I find it to consistently returns more accurate results. I also like being able to monitor my Black component throughout the optimization process. If you have done the “heavy lifting” in Lightroom / ACR then most likely you still have a little “wiggle” room left for Global Luminosity adjustment in Photoshop.

#1. Set image to View-> Fit on Screen

#2. Add a Curve Adjustment Layer (Luminosity Blend Mode) Setting the Blending Mode to Luminosity will insure that whatever adjustment you make only affect the gray scale component of your image and that no shift in hue or saturation will occur. 

#3. Add a Threshold Adjustment Layer (Normal Blend Mode)

#4. Move the slider in the Threshold option dialogue to the left edge of the Histogram

#5. Adjust the slider until you begin to see “significant” areas of Black starting to develop on the white screen. You’re not looking for the first “dot” to appear but rather the first significant “grouping” of dots.

#6. Adjust the slider until that area is just visible. Zoom into that area (1600%) and pick a group of pixels that represent an area of increasing density.

#7. Place the Eyedropper Tool in the center of this Black aggregation and, holding down the Shift Key, click. This will place a Sample Point #1 on the densest point in you image. You can now reference the maximum density with your Info Palette. Once the Sample Point has been set discard the Threshold Adjustment Layer. It was used solely to identify the Black Point and now we have that set. Your image will now return in a zoomed in state. You should see your Sample Point. The Info Palette will now reflect the current maximum density of you image. 

 #8. Select the Global Luminosity layer and open up the Adjustment Palette. Double click on the Black Dropper icon to open up the Color Picker. Double check that your target Black Point is correctly set. I generally use an RGB value of 0,0,0 to insure maximum dMax on the final print. Feel free to experiment with different Black Point settings. Once you’ve confirmed your settings close the Color Picker dialog and with your Black Point Dropper place the tip on Sample Point #1 and click. This will set your Global Luminosity Black point and will insure good solid blacks in your image and provide a strong global framework

#9. Setting the Black Point on a RGB image only adjusts the Luminosity in the individual Red, Green and Blue channels so you can now use the unaltered master curve to adjust the overall contrast. Begin by selecting two points that represent the tonal values you wish to alter. In the image below I selected a light value in the clouds and a dark value in the sky. I specifically avoided areas that were too light or too dark since the purpose of creating contrast was not to clip my highlights or my shadows but rather enhance the difference between the two.

On the Image #1, below, I have indicated the two sample areas I chose and indicated where on the curve those values fell. When I actually implement the adjustments I use the Targeted Adjustment, a convenient way to verify the tonal values you end up selecting. The results are shown in Image #2

 #1

 #2

Global Color Adjustment

A Global Color Adjustment layer is probably my favorite color adjustment tool. In many situations it can save you hours of unfruitful attempts at color-balancing your image. Begin by creating a Curves Adjustment Layer set to Color Blending Mode. Next select your Gray Point Dropper move the tip on to an area of your image that a.) is roughly a midtone (40-60%) and b.) is representative of the color contamination apparent in your image. Click and your image will reflect your new Gray Point. If the change is to your liking you’re done. If not, you can keep moving and clicking on new areas until your image “falls into place”. Remember, as with all Global Adjustments, the adjustment needs to have a positive effect on all areas of the image. If further adjustment is needed in specific areas a Regional Adjustment should be applied later on in the Optimization Process.

Additional Global Luminosity and/or Color Adjustments

I find that generally I am able to make all necessary Global Adjustments with just two Curve Adjustment layers. However, sometime you may need to globally adjust saturation or hue. In that case add the appropriate Adjustment Layer and set it to the target Blending Mode and make your adjustments. (i.e. a Hue/Saturation Adjustment Layer in Saturation Blending Mode to adjust Global saturation.)

These steps outline the Global Adjustments I employ in my Fine Art Digital Workflow.

Next posting: I’ll explore Regional Adjustment.