Before you can start creating your fake abs, you need to have some sort of canvas for the makeup to hold on to. This base or "canvas" can be a foundation that closely matches your skin tone, a tainted moisturizer, or sunscreen. You can also use a tinted sunscreen, or you can create your own by mixing little bit of liquid foundation that is close to your skin tone with your sunscreen. Choose something that suits your needs:  Foundation will give you the most coverage and will help even out your skin tone. A cream foundation will be more opaque than a liquid foundation. A tinted moisturizer will help moisturize and condition your skin, as well as even out your skin tone. It will not have the same coverage as foundation, however. Sunscreen will protect the tender skin on your abdomen against sunburn. If you add some foundation to it, it will also help even out your skin tone a little. You want the bronzer to be about two shades darker than your skin tone. Do not use a shimmering bronzer, as shimmer causes things to pop out—use a matte bronzer instead. You will be creating fake shadows to give the illusion of a toned abdomen, so you want something that looks natural. If you cannot find a non-shimmering bronzer, you can substitute a brown eyeshadow or pressed powder foundation instead, as long as it is no more two shades darker than your skin tone. You want the highlighter to be a shade lighter than your skin tone. This powder can be shiny, as shine causes things to pop out. If you cannot find powder highlighter, you can substitute with pressed powder foundation that is several shades lighter than your skin tone, or a pale ivory eyeshadow. You will need two types of brushes: a large powder brush, and a creasing brush. If you cannot find a creasing brush, you can substitute with a small, round-tipped makeup brush. You will need two of these creasing (or round-tipped) brushes: one for the bronzer, and one for the highlighter. If you cannot find a second creasing brush, you can use the same brush for both the bronzer and highlight. Just make sure you clean the brush by swiping it over a tissue until you cannot see any more bronzer on it. Having a bright light above you will make it easier for you to see your muscles and the shadows they cast. While it is recommended to take off your clothes to prevent staining them with makeup, you can wear an old swimsuit or workout outfit instead. You want your abdomen to be exposed. Do not wear the same outfit that you plan on wearing later with your fake abs. Not only do you risk staining your outfit, but the makeup stains might give your secret away. Do you want a six pack? A four pack? A two pack? Consider this before applying your makeup.
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One-sentence summary -- Choose a foundation, tinted moisturizer, or sunscreen to use as your base. Choose a powder bronzer. Choose a powder highlighter. Find a powder brush and two creasing brushes. Choose a well-lit area. Expose your abdomen. Decide how much muscle you want to add.


If you notice your foundation turns an unpleasant shade of orange whenever you use it, you may want to try going one to two shades lighter than your normal shade. Sometimes, using a lighter shade can make your foundation appear less dark and make any oxidation less noticeable on your skin. The lighter shade will help to counteract the appearance of an orange tinge on your skin, even if oxidation does occur. You may try using a foundation that is one shade lighter than your normal shade in the same brand or switch to a brand that has a wider variety of shades. Make sure you test the foundation properly on your face to ensure the shade is not too light and will still blend well into your skin. Foundation with SPF is made of ingredients like zinc and titanium. These ingredients can then interact with the color products in the foundation, leading to a change in the shade color. You may opt for a foundation that does not contain SPF so you can avoid a reaction on your face that can lead to an orange tinge. Instead, you may invest in a setting powder that contains SPF so your skin is still protected from the sun but it is not at risk of turning orange. You should always test makeup on your skin before you commit to using it full time. You may try wearing a small patch of the foundation on the side of your face for a few hours to make sure it does not react with your skin and create an orange tinge. Or you may apply a full face of foundation and test it out at home for a few hours to ensure the shade does not change color. You should test out all of your makeup products, from foundation to primer to eyeshadow, before you commit to using them on a day to day basis. This will ensure your skin does not have a negative reaction to any of the products.
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One-sentence summary --
Try a lighter foundation shade. Avoid foundations that contain SPF. Test the foundation before you use it.