Fabric Porosity is an important property in determining the functional properties of a fabric. It relates to the count of a yarn as well as to the type of weave. Twill and satin cotton woven fabrics in three different weft densities (warp density kept constant) were used to investigate the effect of porosity on the dyeuptake within one weave. The effects of change in weave type, keeping yarn densities the same, on the porosity were also investigated. Objective determination of porosity was carried out using an image analysis technique while, colour yield was determined using K/S values. Higher the weft density in a satin fabric low will be the porosity of that fabric. Porosity values varied from 6.85-10.98% for S1 and S3 respectively. However, for the twill fabric no substantial change in porosity have been observed as the porosity values varied from 6.4-5.3% for T1 and T3 respectively. Colour strengths for S1 and T1 are lower than S3 and T3 respectively for all the primary colours at 0.25, 1.00 and 2.00% depth levels. It is observed that the change in colour strength is more prominent at 2% depth level as compared to 0.25% depth level