Magic in Scarlet Heroes is very much along the standard D&D style of having spell slots per day for a spell caster with the number of slots and level of the spells that can be taken being based on character level. Spells need to be prepared and can only be prepared once per day with the caster needing to be rested, but there are not rigid rules about how long rest or how long the rituals of spell preparation will take.
The actual spells will seem familiar to players of the OSR games however they do have setting appropriate names which do add a lot to the feel of the game, for example Hand of Merciful Succor is the clerical healing spell and Amber Cloud of Somnolence the magical sleep spell.
There are 8 clerical spells available per spell level and 5 spell levels giving a total of 40 spells. Magic Users have 10 spells per level over the 5 levels to give 50 spells included in the rules. This will probably be enough to cover a lot of situations as the use of the Fray dice will mean that a lot of weak opponents will go down quickly. As rules for researching spells are included it would be possible to add to the these if required.
Magic users will have a limited number of spells in their spellbook that they can learn and to add to these will need to copy from scrolls, other spellbooks or be taught the spell by another wizard. The other alternative is to research spells but that is expensive and time consuming too.
This is part of the game that is not too dissimilar to other OSR role playing games in the D&D style, but I do feel that the use of the different names for the spells does give it a unique flavour appropriate for the setting.