How to Invert Colour Negatives in Photoshop the Easy Way

Are you a photography enthusiast or professional looking to digitise your film negatives? Or perhaps you’ve stumbled upon a collection of old negatives and want to bring them to life digitally. In either case, knowing how to invert colour negatives in Photoshop can be a valuable (albeit challenging) skill. In this guide, I’ll explain a simple process of achieving true-to-life colours and rich tones you typically get from a professional film lab.

Why Invert Colour Negatives?

Before explaining the process, let’s briefly discuss why inverting colour negatives is necessary. Traditional colour film negatives have colours inverted compared to the final print or digital image. It also has an orange mask applied during manufacturing to offset the optical inadequacies of the dyes in the film. Correcting and inverting the colours restores them to their correct hues, making the image viewable and the colours true to life.

Inverting Colour Negatives: The Problem

However, removing the orange film mask in traditional colour photography is challenging for photographers primarily because it alters the colour balance of the entire image. It can be achieved using compensating colour filters to neutralise colour casts in images (and restore accurate colours). But today, it’s digitally performed. But it’s challenging to get right because removing the orange film mask affects the shadows, midtones, and highlights differently. So, subtracting a single colour from negatives doesn’t work perfectly. And neither does relying on the Auto Tone command in Photoshop. Both ways produce inaccurate results—not anymore!

Now, I use this process because:

1. It’s quick,
2. It’s easy,
3. It produces accurate results (well, good enough!).

Also, I will prove the process works using a scan of the X–Rite ColorChecker taken with Fuji Superia 200 (35mm) colour negative film so you can judge the result for yourself.

Moreover, it gets better than this because the process also works with B&W negative film (by omitting the first step).

Invert Colour Negatives: Four Easy Steps!

With that, here are the four easy steps to invert 35mm colour negative film in Photoshop:

• Apply Colour Balance adjustments (to modify colour imperfections)
• Apply Auto Tone (to fix colour casts and contrast)
• Adjust image density (to enhance contrast)
• Invert the image (to produce the correct colours)

Note: This inversion technique works best if you save your scans as linear TIFF files. If not, make fewer contrast adjustments to your images.

Step 1. Apply Colour Balance Adjustments

Firstly, open your image in Photoshop or your chosen photo editing software (See Fig. 1).

Then, apply Colour Balance adjustments (with Preserve Luminosity) to change the overall mixture of colours, helping to modify colour imperfections in the image. Use these settings for good results: Shadows Levels: 0, 0, 0; Midtone Levels: -35, 0, 35; Highlight Levels: -90, 45, 90. You may need to tweak these settings based on how you scan or capture your images, but I find they work well for multiple scans from the same and different film stocks.

After applying Colour Balance adjustments, the R, G, and B values for all neutral tones in the image will be closer to equal (See Fig. 2).

Step 2. Apply Auto Tone (With Auto Neutrals)

Secondly, use a curve adjustment layer and apply Auto Tone (with Auto Neutrals) to neutralise the remaining colour casts in the image (See Fig. 3).

Note: Combining Colour Balance adjustments with Auto Tone to restore colours provides better results than only using Auto Tone (or subtracting the film base colour). Why? Because the Colour Balance adjustments remove most of the orange mask from the shadows, midtones, and highlights—making the Auto Tone feature afterwards more effective.

Step 3. Adjust Image Density

Thirdly, apply another curve adjustment layer and lift the mid-tone value from 128 to 186. This gamma adjustment increases the brightness and contrast in the image, producing rich, vibrant tones (See Fig. 4). This step is necessary if you’re working with linear TIFF files because it converts a linear file to a non-linear one.

Note: Omit this step if working with non-linear files. Otherwise, apply a different gamma adjustment because over- and under-exposed images benefit from density adjustments.

Step 4. Invert the Image

Lastly, invert the image to make the colours in the image positive/correct (See Fig. 5). You can see that the white, mid-grey, and black samples in the image of the X–Rite ColorChecker below are all neutral—check if you like!

Afterwards, you might want to refine the white balance and density to enhance colours and contrast (See Fig. 6). A professional film-developing lab would do the same!

Side-By-Side Comparison

Following the steps outlined in this guide produces images comparable to those from a professional film processing lab (See Fig. 7 below). For example, the image processed by a professional lab on the left is nearly identical to the image processed using the steps outlined above on the right.

Summary

Inverting colour negatives in Photoshop may seem daunting, but following the steps outlined in this guide makes it a straightforward process.

Sure, the inverted images require final touches to enhance white balance and density, but so do images processed using other techniques for removing the orange mask from 35mm colour film.

So, whether preserving cherished memories or digitising 35mm film negatives in Photoshop, mastering this film inversion technique opens up a world of creative possibilities. Start digitising your colour negatives today and unleash your creativity!

Note: All the 35mm photography I shoot (both colour and B&W) is processed using the technique outlined in this colour negative inversion guide.

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