hi I have 10 stopper and you get a lot of color cast some work some don't try converting them into black and white bit of cropping and you might be shocked
Sorry mate I have no idea what this means :s
He means that cheaper 10-stop ND filters produce an unwanted tint in your shots. All your shots have a slight blue hue to them, known as a colour cast. Sometimes this works in your favour, but I think they detract from the shots in this case. The more expensive ND filters, such as B&W, Lee etc. do not have this. By converting to B&W you remove this issue and i personally think it lends itself much better to long exposure work.
Marc it's not the contrast we are talking about, it's the blue cast to all the images that is probably caused by the filter. All you need to do in PP is adjust the white balance slider to remove some of the blue and warm it up. If you are happy with the colour balance you have got then you won't need to do anything as it's you the image has to please unless it's for a client or general sale.