If properly carried out this process will give a black almost equal to aniline black; but having, as already mentioned, the advantage of not impairing the strength of the fibre, and not turning green during storage. As the dye-baths for blacks are charged with a proportionately high percentage of dye-stuff for the first bath, and will not exhaust completely, it is advisable to preserve them for further use. For subsequent lots only two-thirds to three-fourths of the quantities of dye-stuffs used for the first baths are required, which fact has to be taken into consideration when calculating the cost of dyeing. =Dyeing Shot Effects on Satin.=--Not all direct colours are equally well adapted for the production of shot effects; those enumerated in Group I. are most suitable for the purpose, and should be dyed with a larger quantity of soap than is usual for solid shades, in order to leave the silk as little tinted as possible. Dye-stuffs of the other groups may be used if the dyeing is conducted with proper care, _i.e._, keeping the baths more alkaline and lowering the temperature. The goods are dyed with the addition for the two coloured effects previously mentioned, then they are well rinsed, and afterwards the silk is dyed with the suitable acid dye-stuffs, with addition of sulphuric acid at a temperature of about 150 deg. F. Care should be taken not to use too much acid, and to keep the temperature of the bath sufficiently low, as otherwise the acid may cause some of the dye-stuff to go off the cotton and tint the silk. It is best to work at a temperature of about 150 deg. F., with addition of about 3 oz. concentrated sulphuric acid per 10 gallons dye-liquor. For shading the silk all acid dye-stuffs can be used which have been mentioned in the foregoing tables. If in shot effects the cotton is to be dyed bright and full shades, this is best achieved by dyeing with direct colours first, and then topping with basic colours as follows:-- Bottom the cotton first with the suitable direct colours, then dye the silk and then treat the pieces for about two hours in a cold tannin bath (about 8 oz. tannin per 10 gallons of water), then rinse once and pass through a tartar emetic bath (about 3 oz. per 10 gallons), rinse thoroughly and dye the cotton to shade with basic colours in a cold bath to which some acetic acid has been added. Should the silk become a little dull after this process, this may be remedied by a slight soaping. After dyeing rinse well and raise with acetic acid. =Shot Effects with Black Cotton Warp.=--Effects much in favour are designs composed of black cotton and light or coloured silk. The most suitable black dye for this purpose is Diamine black B H, diazotised and developed.