What is an ICC profile, and should you embed it in your image files?

The ICC FAQ says profiles define the relationship between the digital values a device handles and a standard colour space, which lets profiles for different devices be combined [3]. A scanner profile, for example, is made by comparing the RGB values from scanning a test target with the measured colour values for that target [3]. The technote adds that an embedded profile is how a file indicates its colour space [1].

For the basics of colour for print, see our canvas print resolution and colour guide and the colour management guide.

The ICC white paper describes a profile as defining either the image source or its destination [2]. The ICC technote explains the chain. An embedded profile indicates the colour space of the object and defines how its colour data converts into the ICC Profile Connection Space (PCS). From the PCS, the data can be converted to another encoding by applying the desired destination profile [1].

• Source profile: describes the colour space of the image data and how it converts into the PCS [1]. For example, an image tagged as sRGB.
• Destination profile: describes the output colour encoding [1], for example a printer profile built from measurements of a printed target [3].
• PCS: the standard colour space that source and destination profiles both convert through [1][3]. In ICC.1 profiles it is based on CIE colorimetry with the D50 illuminant and the CIE 1931 2 degree observer [1].

The ICC FAQ explains that the PCS restricts the CIE options for illuminant, observer and measurement geometry so that the system is not ambiguous, and that ICC profiles assume a D50 illuminant [3].

Embedding places the profile inside the image file. The ICC white paper says this has the advantage that the profile stays permanently associated with the file, and that this association is not lost in later image processing or file management [2]. The technote lists many formats that can carry a profile, including JPEG, PNG, TIFF, WebP, AVIF, HEIF and PDF [1].

There are limits. The white paper cautions that embedding does not settle use. Whether an embedded profile is applied is up to the software and its colour-management settings [2]. It also warns that if a JPEG reader does not decode the tag correctly, the profile is likely to be damaged or removed when the file is saved again [2].

The ICC registry offers an sRGB v4 preference profile and an sRGB v2 profile [4]. It describes the v4 profile as a replacement for commonly used v2 sRGB profiles, meant to be used alongside other ICC v4 profiles [4]. The registry cautions against mixing its v4 profile with v2 profiles [4].

The technote adds a version note. Higher profile versions are backward compatible, but they may include elements that software built for lower versions does not support [1]. For some formats the allowed version is not specified. PNG is listed as v2 only in the specification, though the technote says current practice supports both [1].

The ICC FAQ says many devices assume sRGB, and that vendors have often done a reasonable job of converting to and from it [3]. The technote says that for WebP, sRGB is assumed if no ICC profile is present [1]. The guides do not state a rule for untagged files in other formats or applications, so do not rely on a default for a print job.

The ICC material describes how profiles are stored. It does not tell you what to do for your own job. These questions are left to you and your print supplier:

• Which profile to embed. The guides explain the mechanism and the sRGB options [1][4], but do not name one profile for every print job.
• Whether your printer's software will use it. The white paper says embedding does not ensure use, because that depends on whether the application is colour-management aware and on its colour-management settings [2]. Our suggestion, not the ICC's: ask your supplier how embedded profiles are handled.
• Whether to convert first. The FAQ describes two cases. If you use an embedded profile with your own output profile, the result will differ from the original supplier's print when the output profiles differ [3]. It suggests asking the original supplier for their output profile and using it to separate the file [3]. It also says a service bureau should convert using the embedded input profile together with the printer profile [3]. Which party converts, and with which profile, is still something to agree with your supplier.
• Which file format. The technote shows what each format can carry [1], not which suits your product.

One option is to keep the profile embedded when you send artwork and to agree the conversion step in writing. Our artwork file checklist covers related file points.

We are a private-label manufacturer in Noida serving businesses and brands only. Samples are paid, and by agreement we can reimburse the cost or adjust it. Payment is 50% advance, and our shipping term is EXW Noida. Ask us how embedded profiles are handled when you brief us. See pricing, minimums and lead times or contact us. We reply within 1 business day.

1. ICC Technical Note: Embedding ICC profiles, International Color Consortium (ICC). archive.color.org
2. White Paper #36: Embedding and referencing ICC profiles, International Color Consortium (ICC). archive.color.org
3. Frequently Asked Questions, International Color Consortium (ICC). archive.color.org
4. sRGB Profiles, International Color Consortium (ICC). registry.color.org