Absolutely you can substitute!
Yes! Any time. That is the fun of creating: You use yarn that you have in the color that you like and make the item. Of course you would not necessarily substitute mercerized cotton with bulk yarn (though that might be a new novel idea), but you can substitute one companies yarn with another or you can move one notch up or down in weight: like sport weight and 4 ply worsted weight. Make a little swatch and see how you like it.
Here is a link to tell you what kinds of yarns are available to work with:
And here is the link to valuable resources to make a global uniformity in the industry:
You do not have to research all this to crochet just for fun, but if you make patterns it is wise to consult, so all pattern makers have the same “lingo”, since our world gets smaller and smaller and we reach all over it with our creations through the internet.
With the substitution will it turn out like the picture in the pattern?
Not quite, since you use different properties with your substitutions. That is perfectly ok, since you WANT to make any of your crochet artwork your OWN. Else you just could buy it at the store. If you substitute something and it doesn’t turn out to your expectation I have a very valuable tip from my long time as a decorative artist: FINISH it ANYWAY! Often I painted with something in mind and when I looked at it, it did not AT ALL looked like what I have in mind, had envisioned or fit my “bill”. However, I finished it anyway- no sense in wasting the material and effort! I put it to the side, disappointed at the time. Later I went back to it and lo and behold: It looked terrific!!!! It was just not what I had in mind that day. Try it! It is amazing.
As you create keep in mind: It is YOUR project and you make one of a kind. Like with any art, your hands have the special touch to make/produce things YOUR way only YOU can do. As special as you are: So is your touch on the materials you use. That is the beauty of creating!
If you want the EXACT item in the pattern, you might as well ask the originator to make it for you. A pattern is developed to produce a certain item with a logical progression, steps towards a finished product that looks similar to the original design. NO way can you expect to have the exact item like on the picture. You need to practice to make an item. Your second item will improve much over the first item. One reason why your second item turns out better is, when you first follow the pattern, you disrupt the flow of a pattern, by constantly reorienting yourself according. As you start and stop your work flow you create differences throughout. Next time you make the pattern, you will be more familiar and your stitches just …flow…. Example the more hats you make, you will already know the size the amount of stitches you need and so on. If you follow a hat pattern to the T you might find your head is a little smaller or bigger and hence you have to adjust, maybe even rip out, which damages/ crinkles your yarn and such. All are ways to prevent an outcome as to what the designer’s picture looks like. Should you be discouraged by this? NO way. Just practice and you probably be a better designer than anybody very soon with very little need for patterns to follow- just create as you go.
To help you as beginners, I designed my pattern scrapbook style, which means: 1. You push the pattern along on your table to keep your place. That helps with not to have to reorient yourself to re-find the place you left off. 2. There are little emblems, cutesy props, change in background ect, which help you to remember where you left off. 3. The layout is attractive, so you enjoy looking at the pattern, instead of dreading to start again. The more patterns I make the better I become with this computer thing.
So why bother even following a pattern?
Following patterns when you first learn to crochet will teach you how many things go together and each in each pattern you will learn something new, which you can utilize later.
If you have any specific question as to how best to substitute: You know I am here for you to help you over Goggle hang out or e-mail.