This invention relates to compounds, compositions and inks, to printing processes, to printed substrates and to ink-jet printer cartridges. Ink-jet printing is a non-impact printing technique in which droplets of ink are ejected through a fine nozzle onto a substrate without bringing the nozzle into contact with the substrate. The set of inks used in this technique typically comprise yellow, magenta, cyan and black inks. With the advent of high-resolution digital cameras and ink-jet printers it is becoming increasingly common for consumers to print off photographs using an ink-jet printer. This avoids the expense and inconvenience of conventional silver halide photography and provides a print quickly and conveniently. While ink-jet printers have many advantages over other forms of printing and image development there are still technical challenges to be addressed. For example, there are the contradictory requirements of providing ink colorants that are soluble in the ink medium and yet do not run or smudge excessively when printed on paper. The inks need to dry quickly to avoid sheets sticking together after they have been printed, but they should not form a crust over the tiny nozzle used in the printer. Storage stability is also important to avoid particle formation that could block the tiny nozzles used in the printer especially since consumers can keep an ink-jet ink cartridge for several months. Furthermore, the resultant images desirably do not fade rapidly on exposure to light or common oxidising gases such as ozone. A particular problem associated with the prints of many ink-jet colourants is the phenomenon of bronzing. This occurs on exposure to light and results in print taking on a metallic sheen. Thus the present invention provides a compound of Formula (1 ) and salts thereof:

Formula (1 ) wherein: M is 2H, Si, a metal, an oxymetal group, a hydroxymetal group or a halometal group; Pc represents a phthalocyanine nucleus of formula; L is a divalent linking group; R1 is SO3H, NO2, NH2 or halogen; R2 is a direct bond to the adjacent oxygen, optionally substituted alkylene or optionally substituted arylene; n is 3 to 20; m is 0 to 20; x is 0 to 3.9; and y is 0.1 to 4. M is preferably 2Li, 2Na, 2K, Mg, Ca, Ba, Al, Si, Sn, Pb, Rh, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, AIX, GaX, InX or SiX2, wherein X is OH or Cl, more preferably Sc, Ti, Va, Cr, Mn, Fe, Co, Zn, Ni and Cu, especially Cu or Ni and more especially Cu. L is preferably -SO2NH-, -SO2O-, -SO2-, -SO-, -O-alkylene-, -0-arylene-, -NH-, -N- alkylene- or -N-arylene- wherein the alkylene or arylene groups may be optionally substituted. It is especially preferred that L is -SO2NH- or -O-alkylene-. When L comprises an alkylene or arylene group said alkylene or arylene group may bear an optional substituent though preferably it is unsubstituted. Preferably R1 is SO3H. Preferably R2 is optionally substituted alkylene, more preferably C1-4 optionally substituted alkylene, especially C1-4 alkylene and particularly -CH2-. Preferably n + m is 3 to 20. In a preferred embodiment preferably when n is 4, m is 3. Preferably x is 0 to 2 and y is 2 to 4. In a preferred embodiment x + y is 4. In another preferred embodiment x is 0. The substituents represented by x or y may be a single group or a mixture of 2 or more different groups. In a further preferred embodiment the substituents represented by x and y are bound to the phthalocyanine ring only through the β-position on the phthalocyanine ring. Preferred optional substituents which may be present on R2 or L, when it comprises an alkylene or arylene group, are independently selected from: optionally substituted alkoxy (preferably C-^-alkoxy), optionally substituted aryl (preferably phenyl), optionally substituted aryloxy (preferably phenoxy), optionally substituted heterocyclic, polyalkylene oxide (preferably polyethylene oxide or polypropylene oxide), carboxy, phosphato, sulpho, nitro, cyano, halo, ureido, -SO2F, hydroxy, ester, -NRaRb, -CORa, -CONRaRb, -NHCORa, carboxyester, sulphone, and -SO2NRaRb, wherein Ra and Rb are each independently H or optionally substituted alkyl (especially C1-4-alkyl). When R2 and L are arylene they may also carry an optionally substituted alkyl (especially Ci-4-alkyl) substituent. Optional substituents for any of the substituents described for R2 and L may be selected from the same list of substituents. The compounds of Formula (1) are also preferably free from fibre reactive groups. The term fibre reactive group is well known in the art and is described for example in EP 0356014 Al Fibre reactive groups are capable, under suitable conditions, of reacting with the hydroxyl groups present in cellulosic fibres or with the amino groups present in natural fibres to form a covalent linkage between the fibre and the dye. As examples of fibre reactive groups excluded from the compounds of Formula (1) there may be mentioned aliphatic sulfonyl groups which contain a sulfate ester group in beta-position to the sulfur atom, e.g. beta-sulfato-ethylsulfonyl groups, alpha, beta-unsaturated acyl radicals of aliphatic carboxylic acids, for example acrylic acid, alpha-chloro-acrylic acid, alpha-bromoacrylic acid, propiolic acid, maleic acid and mono- and dichloro maleic; also the acyl radicals of acids which contain a substituent which reacts with cellulose in the presence of an alkali, e.g. the radical of a halogenated aliphatic acid such as chloroacetic acid, beta-chloro and beta-bromopropionic acids and alpha, beta-dichloro- and dibromopropionic acids or radicals of vinylsulfonyl- or beta-chloroethylsulfonyl- or beta- sulfatoethyl-sulfonyl-endo- methylene cyclohexane carboxylic acids. Other examples of cellulose reactive groups are tetrafluorocyclobutyl carbonyl, trifluoro-cyclobutenyl carbonyl, tetrafluorocyclobutylethenyl carbonyl, trifluoro-cyclobutenylethenyl carbonyl; activated halogenated 1 ,3-dicyanobenzene radicals; and heterocyclic radicals which contain 1, 2 or 3 nitrogen atoms in the heterocyclic ring and at least one cellulose reactive substituent on a carbon atom of the ring, for example a triazinyl halide. Acid or basic groups on the compounds of Formula (1), particularly acid groups, are preferably in the form of a salt. Thus, the Formulae shown herein include the compounds in salt form. Preferred salts are alkali metal salts, especially lithium, sodium and potassium, ammonium and substituted ammonium salts (including quaternary amines such as ((CH3)4N+) and mixtures thereof. Especially preferred are salts with sodium, lithium, ammonia and volatile amines, more especially sodium salts. Compounds of Formula (1) may be converted into a salt using known techniques. The compounds of Formula (1) may exist in tautomeric forms other than those shown in this specification. These tautomers are included within the scope of the present invention. The compounds of Formula (1) may be prepared by any method known in the art. When the compounds of Formula (1) carry substituents only in the β-position they are preferably prepared by a process which comprises cyclisation of appropriate substituted phthalic acid, phthalonitrile, iminoisoindoline, phthalic anhydride, phthalimide or phthalamide in the presence of a suitable source of ammonia (if required), and (if required) a suitable metal salt, for example CuCI2, and a base such as 1 ,8- diazabicyclo[5.4.0]undec-7-ene (DBU) followed by (if required) further synthetic steps, for example, chlorination and then amidation. More preferably, when the phthalocyanine dyes of Formula (1) comprise sulfo and/or substituted sulfonamide substituents in the β-position on the phthalocyanine ring, they are prepared by a process which comprises cyclisation of 4-sulfophthalic acid to phthalocyanine β-tetrasulfonic acid in the presence of a nitrogen source such as urea, a suitable metal salt such as, for example, CuCI2 and a base such as 1,8- diazabicyclo[5.4.0]undec-7-ene (DBU) to give phthalocyanine β-tetrasulfonic acid, a reaction well known in the art, followed by chlorination and then amidation. Phthalocyanines carrying sulfonamides and/or sulfo groups may also be prepared by chlorosulfonating preformed phthalocyanine using, for example, chlorosulfonic acid and optionally a chlorinating agent (e.g. POCI3, PCI5 or thionylchloride). This second protocol will results in a complex mixture of phthalocyanine dye with varying levels of sulfonyl chloride and sulfo substituents in both the α and β-positions. Reaction of the sulfonyl chloride group with an amine then results in sulfonamide. Preferably compounds of Formula (1) comprising a sulfonamide linking group may be prepared by condensing a phthalocyanine derivative (preferably Cu or Ni phthalocyanine) carrying sulfonyl chloride groups with a compound of formula H2N(CH2CH2O)n(CH2CHR2O)rr,CH3 wherein R2 is as hereinbefore defined. Many compounds of formula H2N(CH2CH2O)n(CH2CHR2O)mCH3 are commercially available, for example Jeffamine™M1000, others made be readily prepared by a skilled person. The condensation is preferably performed in water at a pH above 7. Typically the condensation is performed at a temperature of 30 to 7O0C and the condensation is usually complete in less than 24 hours. The compounds of Formula (1) have attractive, strong cyan shades and are valuable colorants for use in the preparation of ink-jet printing inks. They benefit from a good balance of solubility, storage stability and fastness to water and light. According to a second aspect of the present invention there is provided a composition comprising a compound of Formula (1) as described in the first aspect of the invention and a liquid medium. Preferred liquid media include water, a mixture of water and organic solvent and organic solvent free from water. Preferably the liquid medium comprises a mixture of water and organic solvent or organic solvent free from water. When the liquid medium (b) comprises a mixture of water and organic solvent, the weight ratio of water to organic solvent is preferably from 99:1 to 1 :99, more preferably from 99:1 to 50:50 and especially from 95:5 to 80:20. It is preferred that the organic solvent present in the mixture of water and organic solvent is a water-miscible organic solvent or a mixture of such solvents. Preferred water- miscible organic solvents include C1-6-alkanols, preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-pentanol, cyclopentanol and cyclohexanol; linear amides, preferably dimethylformamide or dimethylacetamide; ketones and ketone-alcohols, preferably acetone, methyl ether ketone, cyclohexanone and diacetone alcohol; water-miscible ethers, preferably tetrahydrofuran and dioxane; diols, preferably diols having from 2 to 12 carbon atoms, for example pentane-1 ,5-diol, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol and thiodiglycol and oligo- and poly-alkyleneglycols, preferably diethylene glycol, Methylene glycol, polyethylene glycol and polypropylene glycol; triols, preferably glycerol and 1 ,2,6-hexanetriol; mono-C^-alkyl ethers of diols, preferably mono-C^-alkyl ethers of diols having 2 to 12 carbon atoms, especially 2-methoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)-ethanol, 2-[2-(2-methoxyethoxy)ethoxy]ethanol, 2-[2-(2-ethoxyethoxy)- ethoxy]-ethanol and ethyleneglycol monoallylether; cyclic amides, preferably 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, caprolactam and 1 ,3-dimethylimidazolidone; cyclic esters, preferably caprolactone; sulfoxides, preferably dimethyl sulfoxide and sulfolane. Preferably the liquid medium comprises water and 2 or more, especially from 2 to 8, water-miscible organic solvents. Especially preferred water-miscible organic solvents are cyclic amides, especially 2- pyrrolidone, N-methyl-pyrrolidone and N-ethyl-pyrrolidone; diols, especially 1 ,5-pentane diol, ethyleneglycol, thiodiglycol, diethyleneglycol and triethyleneglycol; and mono-C1-4-alkyl and C1-4-alkyl ethers of diols, more preferably mono- C-^-alkyl ethers of diols having 2 to 12 carbon atoms, especially 2-methoxy-2-ethoxy-2-ethoxyethanol. Examples of further suitable liquid media comprising a mixture of water and one or more organic solvents are described in US 4,963,189, US 4,703,113, US 4,626,284 and EP-A-425,150. When the liquid medium comprises organic solvent free from water, (i.e. less than 1 % water by weight) the solvent preferably has a boiling point of from 30° to 2000C, more preferably of from 40° to 1500C, especially from 50 to 1250C. The organic solvent may be water-immiscible, water-miscible or a mixture of such solvents. Preferred water-miscible organic solvents are any of the hereinbefore-described water-miscible organic solvents and mixtures thereof. Preferred water-immiscible solvents include, for example, aliphatic hydrocarbons; esters, preferably ethyl acetate; chlorinated hydrocarbons, preferably CH2CI2; and ethers, preferably diethyl ether; and mixtures thereof. When the liquid medium comprises a water-immiscible organic solvent, preferably a polar solvent is included because this enhances solubility of the mixture of phthalocyanine dyes in the liquid medium. Examples of polar solvents include C1-4- alcohols. In view of the foregoing preferences it is especially preferred that where the liquid medium is organic solvent free from water it comprises a ketone (especially methyl ethyl ketone) and/or an alcohol (especially a C1-4-alkanol, more especially ethanol or propanol). The organic solvent free from water may be a single organic solvent or a mixture of two or more organic solvents. It is preferred that when the liquid medium is organic solvent free from water it is a mixture of 2 to 5 different organic solvents. This allows a liquid medium to be selected that gives good control, when the composition is used as an ink, over the drying characteristics and storage stability. Liquid media comprising organic solvent free from water are particularly useful where fast drying times are required and particularly when printing onto hydrophobic and non-absorbent substrates, for example plastics, metal and glass. Preferred compositions according to the second aspect of the invention comprise: (a) from 0.01 to 30 parts of a compound of Formula (1) according to the first aspect of the invention; and (b) from 70 to 99.99 parts of a liquid medium; wherein all parts are by weight Preferably the number of parts of (a)+(b)=100. The number of parts of component (a) is preferably from 0.1 to 20, more preferably from 0.5 to 15, and especially from 1 to 5 parts. The number of parts of component (b) is preferably from 99.9 to 80, more preferably from 99.5 to 85, especially from 99 to 95 parts. Preferably component (a) is completely dissolved in component (b). Preferably component (a) has a solubility in component (b) at 200C of at least 10%. This allows the preparation of liquid dye concentrates that may be used to prepare more dilute inks and reduces the chance of the dye precipitating if evaporation of the liquid medium occurs during storage. The compositions may be incorporated in an ink-jet printer as a high concentration cyan ink, a low concentration cyan ink or both a high concentration and a low concentration ink. In the latter case this can lead to improvements in the resolution and quality of printed images. Thus the present invention also provides a composition (preferably an ink) where component (a) is present in an amount of 2.5 to 7 parts, more preferably 2.5 to 5 parts (a high concentration ink) or component (a) is present in an amount of 0.5 to 2.4 parts, more preferably 0.5 to 1.5 parts (a low concentration ink). The liquid media may of course contain additional components conventionally used in ink-jet printing inks, for example viscosity and surface tension modifiers, corrosion inhibitors, biocides, kogation reducing additives and surfactants which may be ionic or non-ionic. Although not usually necessary, further colorants may be added to the ink to modify the shade and performance properties. Examples of such colorants include C.I. Direct Yellow 86, 132, 142 and 173; C.I. Direct Blue 307; C.I. Food Black 2; C.I. Direct Black 168 and 195; and C.I. Acid Yellow 23. It is preferred that the composition according to the invention is ink suitable for use in an ink-jet printer. Ink suitable for use in an ink-jet printer is ink which is able to repeatedly fire through an ink-jet printing head without causing blockage of the fine nozzles. Ink suitable for use in an ink-jet printer preferably has a viscosity of less than 20 cP, more preferably less than 10 cP, especially less than 5 cP, at 25°C. Ink suitable for use in an ink-jet printer preferably contains less than δOOppm, more preferably less than 250ppm, especially less than 100ppm, more especially less than 10ppm in total of divalent and trivalent metal ions (other than any divalent and trivalent metal ions bound to a colorant of Formula (1) or any other colourant or additive incorporated in the ink). Preferably ink suitable for use in an ink-jet printer has been filtered through a filter having a mean pore size below 10μm, more preferably below 3μm, especially below 2μm, more especially below 1 μm. This filtration removes particulate matter that could otherwise block the fine nozzles found in many ink-jet printers. Preferably ink suitable for use in an ink-jet printer contains less than 500ppm, more preferably less than 250ppm, especially less than 100ppm, more especially less than 10ppm in total of halide ions. A third aspect of the invention provides a process for forming an image on a substrate comprising applying ink suitable for use in an ink-jet printer, according to the second aspect of the invention, thereto by means of an ink-jet printer. The ink-jet printer preferably applies the ink to the substrate in the form of droplets that are ejected through a small orifice onto the substrate. Preferred ink-jet printers are piezoelectric ink-jet printers and thermal ink-jet printers. In thermal ink-jet printers, programmed pulses of heat are applied to the ink in a reservoir by means of a resistor adjacent to the orifice, thereby causing the ink to be ejected from the orifice in the form of small droplets directed towards the substrate during relative movement between the substrate and the orifice. In piezoelectric ink-jet printers the oscillation of a small crystal causes ejection of the ink from the orifice. Alternately the ink can be ejected by an electromechanical actuator connected to a moveable paddle or plunger, for example as described in International Patent Application WO00/48938 and International Patent Application WO00/55089. The substrate is preferably paper, plastic, a textile, metal or glass, more preferably paper, an overhead projector slide or a textile material, especially paper. Preferred papers are plain or treated papers which may have an acid, alkaline or neutral character. Glossy papers are especially preferred. A fourth aspect of the present invention provides a material preferably paper, plastic, a textile, metal or glass, more preferably paper, an overhead projector slide or a textile material, especially paper more especially plain, coated or treated papers printed with a compound as described in the first aspect of the invention, a composition according to the second aspect of the invention or by means of a process according to the third aspect of the invention. It is especially preferred that the printed material of the fourth aspect of the invention is a photograph printed using a process according to the third aspect of the invention. A fifth aspect of the present invention provides an ink-jet printer cartridge comprising a chamber and an ink suitable for use in an ink-jet printer wherein the ink is in the chamber and the ink is as defined in the second aspect of the present invention. The cartridge may contain a high concentration ink and a low concentration ink, as described in the second aspect of the invention, in different chambers. The invention is further illustrated by the following Examples in which all parts and percentages are by weight unless otherwise stated.

Example 1 Preparation of:

Phosphorous oxychloride (3.07g) was added dropwise to chlorosulfonic acid (29.13g) over 5-10 minutes while keeping the temperature below 300C. When all the POCI3 had been added, copper phthalocyanine (2.94g) was added portion-wise while keeping the reaction temperature below 6O0C, this addition took 5-10 minutes. The reaction mixture was stirred at 50-600C for 15-20 minutes. The temperature of the reaction mixture was then gradually increased to 138-1400C over 30 minutes, held at this temperature for 5h and then stirred overnight at room temperature. The mixture was added to water/ice/NaCI/ concentrated HCI (50ml/50g/3g/1.5ml). The solid that precipitated was filtered, washed with ice cold acidified 5% salt solution and pulled dry using a vacuum pump. The resultant damp paste was then added in portions to Jeffamine™ M1000(40g) in water(IOOml) at 0°-10°C and the mixture was stirred at 0° to 1O0C (pH 10.5-11) for O.δhours. The reaction mixture was then stirred at 40°C, pH 10.5 for 3 hours, at room temperature overnight and at 80-850C, pH 10.5 for a further 2hours. At the end of this time reaction mixture was neutralised with HCI and then dialysed to remove salts and excess jeffamine M1000. Water was removed in vacuo followed by oven drying to yield a viscous cyan coloured liquid (14.96g) with absorbance maxima at 628nm and 666nm. Example 2 Preparation of:

CUPC-(O-(CH2CH2O)7CH3).,

Stage 1 4-Nitrophthalonitrile (25g), PEG350 methyl ether (79.5g), potassium carbonate (4Og) and dimethylsulfoxide (50ml) were stirred at room temperature under nitrogen in a clean dry flask. After two days analysis by TLC showed that the all of the 4- nitrophthalonitrile was consumed and the reaction mixture was poured onto water (200ml). The product was extracted with ethylacetate (3x100ml) and the combined extracts were washed with water (2x50ml), and dried over MgSO4. The drying agent was removed by gravity filtration and the solvent was removed in vacuo to yield a dark brown oil (6.5g, 96%).

Stage 2 A clean dry flask was charged with pentanol (100ml) and degassed with nitrogen for 15mins. The product of stage 1 was added (1Og) along with phthalonitrile (2.8g) and DBU (6.5g). Finally copper (II) chloride (anhydrous, 1.44g) was added under a stream of nitrogen and the reaction mixture was heated to reflux for 5 hours. The pentanol was removed in vacuo and the product was dissolved in water (500ml). Sodium chloride was added (75g) to the solution and the pH was adjusted to pH 4 with concentrated HCI. The precipitate that formed was collected and pulled dry using a vacuum pump. Both the filtrate and the solid fractions were separately dissolved in water (300ml), pH adjusted to 9 and then dialysed to give two fractions of the title compound when dried down. The absorbance maxima of both fractions were 628 and 666 nm.

Comparative Dye The comparative dye has the following structure

and was prepared as described in Example 5 of International Patent Application WO2004/035701. Phthalocyanines of this general type bearing sulfo, sulfonamide and substituted sulfonamide substituents are widely used in ink-jet printing. Preparation of Inks Inks were prepared from the dyes of Examples 1 (Ink 1) and 2 (Ink 2) and the Comparative Dye (Comparative Ink) by dissolving 3 g of the dye in 97 ml of a liquid medium consisting of 5 parts 2-pyrrolidone; 5 parts thiodiethylene glycol; 1 part Surfynol™ 465 and 89 parts distilled water and adjusting the pH to between pH 8 to 9 with sodium hydroxide. Surfynol™ 465 is a surfactant from Air Products. Inks such as this have a viscosity of less than 20 cP at 25°C; less than 500ppm in total of divalent and trivalent metal ions (other than any divalent and trivalent metal ions bound to a colorant of Formula (1) or any other component of the ink); and less than 500ppm in total of halide ions.

Ink-jet Printing Inks, prepared as described above, were filtered through a 0.45 micron nylon filter and then incorporated into empty print cartridges using a syringe. These inks were then printed onto Xerox 4024 Premium Multipurpose White Paper (Xerox 4024), HP Premium Plus Photo Paper (HPPP) Epson Premium Glossy Photopaper ("SEC PM") and Canon PR101 Photopaper (PR101 ).

Print Evaluation Bronzing of the printed image is assessed visually using an arbitrary scale of 0 (no bronzing) to 10 (heavy bronzing).

Results

Thus, compounds of the present invention provide prints which display improved bronzing characteristics on a range of ink-jet media.

Further Inks The inks described in Tables A and B may be prepared wherein the Compound described in the first column is the Compound made in the above Example of the same number. Numbers quoted in the second column onwards refer to the number of parts of the relevant ingredient and all parts are by weight. The inks may be applied to paper by thermal or piezo ink-jet printing. The following abbreviations are used in Tables A and B: PG = propylene glycol DEG = diethylene glycol NMP = N-methyl pyrollidone DMK = dimethylketone IPA = isopropanol MEOH = methanol 2P = 2-pyrollidone MIBK = methylisobutyl ketone P12 = propane-1 ,2-diol BDL = butane-2,3-diol CET= cetyl ammonium bromide PHO = Na2HPO4 and TBT = tertiary butanol TDG = thiodiglycol TABLE A Ni TABLE B ω