Watermarking spot colors

Osama M. Alattar; Alastair M. Reed

doi:10.1117/12.477305

20 June 2003 Watermarking spot colors

Osama M. Alattar, Alastair M. Reed

Proceedings Volume 5020, Security and Watermarking of Multimedia Contents V; (2003) https://doi.org/10.1117/12.477305
Event: Electronic Imaging 2003, 2003, Santa Clara, CA, United States

Abstract

Watermarking of printed materials has usually focused on process inks of cyan, magenta, yellow and black (CMYK). In packaging, almost three out of four printed materials include spot colors. Spot colors are special premixed inks, which can be produced in a vibrant range of colors, often outside the CMYK color gamut. In embedding a watermark into printed material, a common approach is to modify the luminance value of each pixel in the image. In the case of process color work pieces, the luminance change can be scaled to the C, M, Y and K channels using a weighting function, to produce the desired change in luminance. In the case of spot color art designs, there is only one channel available and the luminance change is applied to this channel. In this paper we develop a weighting function to embed the watermark signal across the range of different spot colors. This weighting function normalizes visibility effect and signal robustness across a wide range of different spot colors. It normalizes the signal robustness level over the range of an individual spot color’s intensity levels. Further, it takes into account the sensitivity of the capturing device to the different spot colors.

Citation Download Citation

Osama M. Alattar and Alastair M. Reed "Watermarking spot colors", Proc. SPIE 5020, Security and Watermarking of Multimedia Contents V, (20 June 2003); https://doi.org/10.1117/12.477305

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available