Abstract: A quantitative evaluation of a color filter (10) in accordance with the capacity of said filter to restore hues comprises the use of a numerical color appearance model. Values of a perceptive attribute are calculated for hue samples (20), by simulating the observation of each of the samples through the filter (10) and without a filter. The values of the perceptive attribute correspond to the visual perception of the samples by an observer (40), and a deviation between the values with and without filter constitutes the result of the evaluation of the filter. Such a method makes it possible to quantitatively rank several color filters, and the ranking obtained corresponds to that which would be established by real observers evaluating the filters.

Abstract: A method of improving an initial color filter comprises a numerical generation of sinusoidal spectra. Two steps of selecting said spectra are then executed. The first selection is carried out according to a criterion of calorimetric similitude with respect to the initial filter. The second selection is carried out according to the capacity of dummy filters corresponding to each spectrum to restore hues in a natural manner. To do this, observations of samples of hues through each dummy filter are simulated numerically, using a color appearance model to take account of a visual perception of a human observer. In this way, an improved filter is determined, which has a color close to that of the initial filter and which affords a natural rendition of hues.

Abstract: A quantitative evaluation of a color filter (10) in accordance with the capacity of said filter to restore hues comprises the use of a numerical color appearance model. Values of a perceptive attribute are calculated for hue samples (20), by simulating the observation of each of the samples through the filter (10) and without a filter. The values of the perceptive attribute correspond to the visual perception of the samples by an observer (40), and a deviation between the values with and without filter constitutes the result of the evaluation of the filter. Such a method makes it possible to quantitatively rank several color filters, and the ranking obtained corresponds to that which would be established by real observers evaluating the filters.

Abstract: The invention concerns a method which consists in irradiating at least one face of the article with UV radiation, causing the article to be photodegraded over a thickness of at least 1 ?m, and in contacting the irradiated face of the article with a colouring agent so as to diffuse the colouring agent in the entire thickness of the photodegraded surface layer of the article. The invention is useful for optical and ophthalmologic articles.

Abstract: The invention concerns a method which consists in irradiating at least one face of the article with UV radiation, causing the article to be photodegraded over a thickness of at least 1 ?m, and in contacting the irradiated face of the article with a colouring agent so as to diffuse the colouring agent in the entire thickness of the photodegraded surface layer of the article. The invention is useful for optical and ophthalmologic articles.

Abstract: The invention concerns a method which comprises irradiating at least one face of an article with UV radiation, causing the article to be photodegraded over a thickness of at least 1 ?m and contacting the irradiated face of the article with a coloring agent, so as to diffuse the coloring agent in the entire thickness of the photodegraded surface layer of the article. The invention is useful for optical and ophthalmologic articles.

Abstract: The method comprises introducing into a reactor including a transparent polymer substrate containing a free plasticizer and the photochromic additive, supercritical fluid and maintaining this fluid in the reactor for the time necessary for incorporating the photochromic additive into the article, removing the supercritical fluid and recovering the ophthalmic article in which the photochromic additive has been incorporated.

Abstract: The invention concerns a method which comprises irradiating at least one face of an article with UV radiation, causing the article to be photodegraded over a thickness of at least 1 &mgr;m and contacting the irradiated face of the article with a coloring agent, so as to diffuse the coloring agent in the entire thickness of the photodegraded surface layer of the article. The invention is useful for optical and ophthalmologic articles.

Abstract: The method comprises introducing into a reactor including a transparent polymer substrate containing a free plasticizer and the photochromic additive, supercritical fluid and maintaining this fluid in the reactor for the time necessary for incorporating the photochromic additive into the article, removing the supercritical fluid and recovering the ophthalmic article in which the photochromic additive has been incorporated.

Abstract: The invention concerns a method which comprises irradiating at least one face of an article with UV radiation, causing the article to be photodegraded over a thickness of at least 1 &mgr;.m. and contacting the irradiated face of the article with a coloring agent, so as to diffuse the coloring agent in the entire thickness of the photodegraded surface layer of the article. The invention is useful for optical and ophthalmologic articles.

Abstract: The method comprises introducing into a reactor including a transparent polymer substrate containing a free plasticizer and the photochromic additive, supercritical fluid and maintaining this fluid in the reactor for the time necessary for incorporating the photochromic additive into the article, removing the supercritical fluid and recovering the ophthalmic article in which the photochromic additive has been incorporated.