Getting to True White: A Photoshop Workflow That Actually Works for Product Shots
There is a specific kind of frustration that only product photographers understand. You nail the shot. The lighting is clean, the product looks sharp, and your backdrop looks white in the studio. Then you upload the image to a website or hand it off to a client, and suddenly there is a faint gray or bluish border framing the whole thing. The background was never actually white. It just looked white. For e-commerce, that difference is everything. Retailers like Amazon require true white backgrounds (RGB 255, 255, 255), and even if you are not selling on a marketplace, a near-white background reads as unprofessional the second it sits next to other product images on a page.
I have been fixing this problem since before I knew there was a systematic way to fix it. I used to over-brighten in Lightroom and blow out product edges in the process. Then I watched this Aaron Nace tutorial from PHLEARN, and it reframed the whole thing for me. He teaches a method that uses Photoshop’s threshold adjustment layer as a diagnostic tool first, before making a single destructive edit. That order of operations matters more than most tutorials acknowledge. Watch the full tutorial on YouTube if you want to follow along with his demo image, but everything you need to replicate the technique on your own photos is below.
The sample image in the tutorial is a product shot of a strawberry submerged in milk. It is a gorgeous concept photo, but the milk reads as a cool, slightly blue-tinted off-white instead of pure white. That is exactly the kind of subtle cast that looks fine on a gray desktop background and terrible on a white webpage.
Step 1: Use a Threshold Layer to Diagnose What You Are Actually Working With
Threshold adjustment layer panel open in Photoshop
Before you change anything, you need to see the truth about your image. Add a Threshold adjustment layer by going to the Adjustments panel and selecting Threshold. This layer converts your entire image to pure black and pure white based on a luminosity cutoff point. Drag the slider all the way to the right. At this extreme, any pixel that is not RGB 255, 255, 255 will appear black. If your background shows up as solid black at that slider position, you have zero pure white in the image. That is your baseline. This is not a layer you will keep in the final file; it is a diagnostic tool, like a light meter reading before you set your exposure.
Step 2: Confirm Pure White Is Possible by Painting a Test Swatch
White paint swatch showing as white in threshold view
With the threshold layer still active and the slider pushed all the way to the right, create a new blank layer beneath the threshold layer. Grab the brush tool, set your foreground color to pure white (RGB 255, 255, 255), and paint a small stroke somewhere on the canvas. That stroke will immediately appear white through the threshold layer, confirming that the layer is working correctly and that pure white is achievable. You will also see a corresponding spike appear at the far right of the histogram. Once you have confirmed this, hide or delete that test layer. You are not fixing anything yet; you are just learning what the threshold layer is actually telling you.
Step 3: Remove Color Casts with a Hue/Saturation Adjustment Layer
Hue Saturation panel with saturation dragged to zero
Color casts are usually the first obstacle between a near-white background and a true white one. Add a Hue/Saturation adjustment layer above your image layer. Drag the Saturation slider all the way to -100. This strips the color from the entire image, which is obviously not the goal for a product with color (like a red strawberry), but it is a fast, clean way to neutralize a background with a blue, yellow, or green tint. The threshold layer above it will immediately show you whether this move is pushing your background closer to white.
Step 4: Mask the Hue/Saturation Layer to Protect the Product
Black brush painting over strawberry on layer mask
Because you only want to desaturate the background and not the product itself, you need to paint the Hue/Saturation adjustment back out over the product area. Click on the white layer mask thumbnail attached to the Hue/Saturation layer. Select a soft brush with black as your foreground color. Paint over the product, including any areas where product meets background (like the splash zones in the milk shot). Black on a layer mask hides the effect; white reveals it. You are essentially drawing a line that says: remove the color cast here, but leave the product alone. Work carefully around the edges. This is the step that determines whether your final image looks natural or over-processed.
Step 5: Check Your Progress Against the Threshold Layer
Threshold layer showing background areas still appearing black
Toggle the threshold layer’s visibility on and off as you work through your adjustments. Each time you make a change, pull the threshold slider back to the far right and check whether your background areas are now showing up as white rather than black. This is the only objective way to know whether you have actually reached 255, 255, 255 or just gotten close enough to fool your eye. Your eye will lie to you. The threshold layer will not. If parts of the background are still showing black after the hue/saturation step, you may need to add a Curves or Levels adjustment layer targeted at the background to push those remaining tones into true white.
Step 6: Preview the Image on White to Catch Any Remaining Borders
Gray border visible around image against white page
One of the most useful things Aaron demonstrates is how to preview your image against a white canvas inside Photoshop before you export. Create a new solid white layer beneath everything in your layer stack. This simulates what the image will look like on a white webpage or printed on white paper. Any remaining gray fringe or off-white area will be immediately visible as a border or halo. This step has saved me from delivering images that looked fine in Photoshop and embarrassing in the client’s online store. It takes thirty seconds and it is worth it every single time.
A Note on When to Fix It in Camera Instead
The threshold method is reliable, but it works harder when the original image is far from white. If I am shooting in my lightbox, I always check my background exposure separately before I even place the product. I use a spot meter reading off the backdrop and aim to expose it at least one stop brighter than the product. That gets me to a background that reads around 230-240 in RGB, and the Photoshop work becomes a minor correction rather than a recovery job. The tutorial technique is excellent for images you receive from clients, archival work, or shots taken in less controlled conditions. For your own shoots, reducing the distance between “close to white” and “pure white” before you open Photoshop will always produce better results than correcting a heavily tinted background in post.
The single most important idea in this whole workflow is using the threshold layer as a measurement tool, not an editing tool. Most people skip the diagnostic step and go straight to brightening, which leads to blown-out product edges and backgrounds that are bright but still not white. Measure first, then correct. It is the same logic that applies to good lighting, and it applies just as well in post.
Watch the full tutorial on YouTube to see Aaron walk through this on his demo image, including the bonus technique for creating a pure black background using the same diagnostic approach in reverse.