When I need to make a print, I have a step-by-step checklist that I go over to minimize preventable errors. The last thing I want to do is send my file to lab for an expensive large print and then notice a dust spot when it’s hanging on my wall.
1 - Calibrate your Monitor
If I haven’t calibrated and profiled my monitor recently, I will do so before starting to work on an image for print. I have an i1 Color Munki Display (which is now sold as an i1 Display Studio for about $150). I initially started by using the manufacturer’s software but have since switched to the open source DisplayCAL which allows many more patches to be sampled.
2 - Check for Artifacts at 100%
I go over my image multiple times at 100 or 200% magnification and look for any artifacts or issues that I need to fix. This could be
- dust spots
- excessive halos
- small pieces of garbage in the scene (normally I try to pick them up before photographing but that’s not always possible)
- small birds that might look like black dust spots in a print
- small bright objects that will look like the ink flaked off the print
- moire (sometimes appears in cityscapes when buildings have regular textures)
- small twigs or other objects that look out of place
In most cases I can modify my exisiting file (add a layer in PS for clone stamping or add spot cloning adjustments in Lightroom). However some issues like halos may require reprocessing from the start.
If you have a hard time seeing dust spots, you can toggle the “Visualize Spots” option in Lightroom. This will make faint dust spots in the sky or other smooth areas stand out. In Photoshop, I may add a temporary curves adjustment layer and increase the contrast to make the spots more visible.
Visualize spots in Lightroom. When this option is selected, Lightroom shows edges in the image and dust spots often show up as very visible circles.
3 - Check for Image Brightness
I think the number one issue for prints is that they often come out too dark. This can happen even with a calibrated monitor, in part because our eyes adapt to our environment so even a dark image looks good after a bit of time staring at it. We also edit our images on a display that transmits light versus a print that reflects light.
To prevent dark prints:
- Use a suitable brightness for your monitor. The exact brightness should be balanced with the ambient light in the room. I edit in a bright room so I set the brightness of my monitor to 130 cd/m^2. I have heard other photographers use anywhere from 60-140 cd/m^2 depending on their setup – there isn’t a single right answer here. The brightness should be set to give the closest visual match to your prints. If you don’t have a monitor calibrator, turn down the brightness of your monitor as most are way too bright. My monitor is only set to about 30-40% of maximum.
- Look at the histogram and make sure there is full coverage to the 0 and 255 levels for images with a normal range of tones (i.e. that should have true black and white areas). You can also adjust white and black point sliders in lightroom holding down the option/alt key to see what is starting to clip.
- Check the image against a white background (right click in LR/PS on the background to change the color) and adjust brightness. A white background will more closely approximate how the image will look on a paper print. Some people edit against a white background but I find that too uncomfortable for my eyes so I use a middle gray and then switch to white near the end.
Histogram of well balanced image using the full tonal range. The upper and lower tails of the distribution should just touch the left and right edges (the left edge represents pure black and right edge represents pure white).
Editing an image on a white background. Compare how the tones feel compared to the situation below using a black background.
The same image on a black background. With the dark surround, the low wall in the foreground and the dirt in front feels much brighter and attracts more visual attention than I intended. A dark background can fool you into thinking the image is brighter than it actually is leading to dark prints.
4 - Check for Color Gamut Issues & Soft Proof
Before printing I check to see if there are any out-of-gamut colors. This can often be an issue when printing highly saturated sunsets or flowers. If unaddressed, this can result in shifted colors, lack of detail, and posterization or banding.
If you have an ICC profile for your paper, you can see gamut warnings in Lightroom. Go to the Develop module, toggle the soft proofing button, set the profile to your paper, and then toggle the warning indicator in the top right of the histogram. These gamut warnings work regardless of whether your monitor is calibrated or not.
If your monitor is calibrated, you can directly see color issues with soft proofing and adjust your colors (hue, saturation, lightness) appropriately before doing a test print. Otherwise you may have to guess a bit and use hard proofs to verify.
5 - Check Sharpening
When it comes to sharpening my images, I follow a two stage process:
- Capture sharpening of the RAW files – to reverse the bluriness induced by the lens imperfections, anti-aliasing filters, and demosaicing the bayer filter over the sensor.
- Output sharpening of the print file – to counteract the bluriness induced by the printing process. For example, when you print to a paper, the ink soaks into the surface and may expand a bit. Output sharpening is designed to counteract this softening.
It’s beyond the scope of this article to describe capture and output sharpening in depth (there could be a whole book written on each). But in general, I use the detail panel in Lightroom (or Adobe Camera Raw) to apply capture sharpening and I try to make the image look good at 100% without any visible halos or artifacts. When in doubt, I back off as sharpening can always be added later but is very hard to remove if overdone.
Impact of capture sharpening. On the left is a 100% crop of architectural detail from an image with no capture sharpening (amount = 0 in Lightroom’s detail panel). On the right is the same image with capture sharpening set to amount = 40, radius = 0.5, detail = 100, masking = 0. Click on the image to see it at 100% (should be 800 pixels wide)
For output sharpening of small prints, I use the default output sharpening available in Lightroom through the printing module or through the export dialog.
Output sharpening in Lightroom’s print module
Output sharpening in Lightroom’s export dialog
For larger prints, I may apply output sharpening in PS using layers. A good default option is to use PhotoKit which has settings for continuous tone (e.g. a lightjet making photographic prints), halftone, and inkjet prints (with matt and glossy finishes). Alternatively, I may use a custom approach with different sharpening algorithms applied on separate layers with masking.
When in doubt, I will crop my image and make a small test print at the same PPI as my intended output to evaluate the sharpening.
6 - Make a Hard Proof
At this point I will make a hard proof and check color and brightness. Ideally this is done on the same printer and paper as the final intended output, but even a different paper can help reveal issues as papers often have similar brightness and gamut.
I print a small version and I look at it in different lighting conditions around my home. If I see any issues I revise my file and repeat. I also sometimes find additional spots that need to be clone stamped.
7 - Check the Output File Format
If I’m printing at a lab, I’ll double check my export settings and verify that the ICC profile was embedded. Normally for me this is a jpeg file with in the AdobeRGB colorspace saved at 100% quality.
I’m also paranoid about dust spots, so I’ll often re-check a few times before sending off the file for printing.
What if I Don’t Have a Calibrated Monitor?
If you don’t have a calibrated monitor, you are going to have a harder time ensuring that the color and brightness of your prints are correct. But it’s not a completely impossible task, you will have to rely on techniques based on the numbers like checking that the histogram covers the full range of values. You will also probably need to go through multiple iterations of printing a proof copy and revising your image file.
If you are using an external lab to make your proofs, make absolutely sure that you have disabled the auto-correct option. I’d recommend using someplace inexpensive and local (my choice would be Costco’s photo center) and print multiple 4x6 variants at time when considering different revisions.