How to digitally colour a black & white photograph is like any other learning curve, you need firstly to have a desire or an urge to colour your old black/white photos, good image software, quality flat bed scanner and a few select manipulation programs such as the invaluable ones we use and cannot do without.
Your first and last undertaking is to practice, practice and more practice, as they say "practice makes perfect", and this adage is never more true as when attempting to restore, repair, enhance or colorize an image, the learning is constant because each image stands alone, meaning that no two images can be considered the same even if they look the same.
You cannot apply the same selected values from your software program that you have used to enhance one image and expect it to produce the same result in another image that may appear to be the same as the first, the key is the lighting effect from image to image, the level of deterioration an image has suffered in loss of resolution and to the, extent by percentage, such loss or damage has occurred.
Perhaps I can best explain by telling you, we once selected two photos in sepia tone that were taken before 1890, both photos had been taken by the same photographer and in the same studio, each of the photos appeared almost identical in the pose, lighting and resolution and level of damage or loss, to all intent and purpose they were almost duplicates, other than they were of different subjects.
For the first image we logged every value selection that we made from each of the software we were using, we saved the progress of our work at given points from start to finish and in a given order, we then attempted to follow the precise step by step with the second image, only to find that while we were happy with end result of the first image, the second image fell far short of the mark, we learned an invaluable lesson that day.
Having selected your photo from your family album you now need to scan it and save it to a folder on your computer, if the photo is a head and should portrait you should scan at a minimum of 300dpi at default setting, if the image is of a longer shot or full body, then scan at a minimum 500dpi, and for distance shots, commonly know as mountain settings, scan at a minimum 600dpi.
Let assume you have scanned a head and shoulder image, you have imported the image into your editing software and you are ready to commence, your colouring will need to include eyes and hair because they are close enough to the camera for colours to be evident, whereas full body images rarely require eye colour to be so precise as they are to far away, and for scenic shots the colours are as you wish to adopt.
I am going to assume here that your image is intact and requires no repairs to rebuild lost sections or lost or faded resolution, such work does require a lot of practice to be able to achieve even some moderate results because the more rebuilding tends to transform a photo image into a painted image and in many instances are poor painting at that.
Now you have the image in your editor you want to start like an artist, start by colouring background working forward to the smaller areas such as the face and the eyes last, if they are your own family images then you can use your colours that are predominant in your family, although and unless you know for certain your colour traits, it is the only option you have.
I am unable to provide value selections when colouring if you're imaging software is not Adobe Photoshop as it is the only one we have ever used, but it is better you learn by trial and error because what you learn tends to stick in ones mind better, but as a guide, for the skin colour, you can try using the following Adobe values:
Convert your image to true black and white. Select the 'brush' tool, set to 'overlay' and 'opacity' at 10% at a size around 30%.
From your 'colour picker' select #9d7661and make one pass over the skin area without taking your finger off the left mouse button until entire area of skin is covered, do all skin areas same.
From your 'colour picker' now select #ea5a5a with 'opacity' at 4% and brush size as above and work the brush over the cheek area only for female, include nose area for
Male, slightly increase opacity, or go over twice, for older males.
You should now be somewhere close to your desired skin colour, but remember all these values and pressure percentages should be adjusted until you are happy with the result, now selecting all other colours for eyes, hair, clothing and backdrop, using the 'overlay' selection and various values you can totally colour your image, if you are not satisfied with what you see then adjust until you are, I also recommend using 'Save As' often so as not to lose your work in the event of a crash etc.
If you practice over and over again you will certainly see improvements in a short time. We are always available to answer your questions (if possible) via our website, good luck and we hope you enjoy, as much as we do the amazing transformations you will see to your old photographs.